Disconnect assembly for cylindrical members

ABSTRACT

Disclosed is an assembly for disconnecting portions of a downhole tubular string, such as a drill stem or drill string, and removing an upper portion of the tubular string from the lower stuck portion in a well. The disconnect assembly includes a connection between joints of two portions of the tubular string. The assembly includes two tubular members and an inner sleeve having two splines each with different angular pitches or teeth counts. The assembly may include a rotary shouldered threaded connection, wherein the two tubular portions are disconnectable at the rotary shouldered threaded connection in the assembly. The assembly may include a sleeve lock, a selective no-go for landing in a profile, and a selectively deployable unlocking and unblocking tool for activating the assembly. The assembly may include connectable cylindrical members other than downhole tubulars.

BACKGROUND

This disclosure relates to releasable connections between cylindricalmembers or bodies. In some aspects, this disclosure relates toconnections between downhole tubulars, such as drill pipe tool joints,as are employed in the rotary system of drilling. More particularly, thedownhole tubular connections or drill pipe tool joints includeconnections configured to be selectively disconnectable within the wellbore, such that upper and lower portions of the downhole tubular stringcan be separated.

In drilling by the rotary method, a drill bit is attached to the lowerend of a drill stem composed of lengths of tubular drill pipe and othercomponents joined together by tool joints with rotary shoulderedthreaded connections. In this disclosure, “drill stem” is intended toinclude other forms of downhole tubular strings such as drill stringsand work strings. A rotary shouldered threaded connection may also bereferred to as a RSTC. Furthermore, the tubular members that make up adrill stem may also be substituted with other rods, shafts, or othercylindrical members that may be used at the surface and which mayrequire a releasable connection.

The drill stem may include threads that are engaged by right hand and/orleft hand rotation. The threaded connections must sustain the weight ofthe drill stem, withstand the strain of repeated make-up and break-out,resist fatigue, resist additional make-up during drilling, provide aleak proof seal, and not loosen during normal operations.

The rotary drilling process subjects the drill stem to tremendousdynamic tensile stresses, dynamic bending stresses and dynamicrotational stresses that can result in premature drill stem failure dueto fatigue. The accepted design of drill stem connections is toincorporate coarse tapered threads and metal to metal sealing shoulders.Proper design is a balance of strength between the internal and externalthreaded connection. Some of the variables include outside diameter,inside diameters, thread pitch, thread form, sealing shoulder area,metal selection, grease friction factor and assembly torque. Thoseskilled in the art are aware of the interrelationships of thesevariables and the severity of the stresses placed on a drill stem.

The tool joints or pipe connections in the drill stem must haveappropriate shoulder area, thread pitch, shear area and friction totransmit the required drilling torque. In use, all threads in the drillstring must be assembled with a torque exceeding the required drillingtorque as a minimum, or more to handle tensile and bending loads withoutshoulder separation because shoulder separation causes leaks andfretting wear.

Drill stem and tool joints with rotary shouldered threaded connectionsare addressed by industry accepted standards such as, but not limitedto: International Industry Standard (ISO), ISO 10424-1:2004(modified)—Part 1 and Part 2; Petroleum and natural gasindustries-Rotary drilling equipment—Part 1: Rotary drill stem elements;American Petroleum Institute (API), API 7-1 Specification for RotaryDrill Stem Elements; API 7G Recommended Practice for Drill Stem Designand Operating Limits; and others. These standards address design,manufacture, use and maintenance of drill stem thread joints.

Offshore drilling, for example, is performed in progressively deeperwater, with deeper penetration of the earth and possibly having higherdeviations from a vertical bore hole. Further, many wells now havesections of horizontal bore hole. The temperatures are high, thefriction between drill stem and borehole is high, the hanging weight isextreme and the well bores may not be straight. Consequently, a portionof the drill stem often becomes stuck at a great distance from thesurface, preventing its movement and recovery. Further causes of stuckdrill pipe include accumulation of cuttings falling out of circulatedfluids, unconsolidated earth caving in the borehole, low pressure stratacapturing the drill stem due to differential pressure, and the like.

In rotary drilling, to remove stuck drill stem from the well, typicallythe first remedial action is to identify the point at which the drillstem is stuck. A decision is then often made to either explosivelyloosen a thread joint or sever the drill stem with highly reactiveexplosive or chemical tools.

Highly specialized crews, equipment and tools must be mobilized andtransported to the well location. The transportation of explosive orhighly reactive chemical tools is subject to tight governmentalregulation. The use of such explosive or highly reactive chemical toolspresents a risk to the well operation in that the possibility existsthat accidental discharge on the surface can cause property damage andinjury or death to personnel. Mobilization and transportation canconsume a significant amount of expensive, non-productive time.

Current tubing disconnects designed for within-the-well-bore activationare lacking. In the discussion below, tubing disconnects are disposed inwork strings or pipe strings used for coiled tubing drilling, wellcompletion, workover, and other services less demanding than rotarydrilling. Consequently, current tubing disconnects do not meet therequirements of the ISO and/or API specifications for rotary drillingequipment. They incorporate non-shouldered connections and/orconnections that do not establish a stress pattern within the connectionto prevent shoulders from separation under extreme tension and/orbending loads.

Further, current tubing disconnects employ non-metal seals. Failure ofone of these seals may result in a washout or total joint failure. Thesliding fit of the seals facilitates fretting and wear as the tubing isflexed in response to axial, bending and rotational forces. Some tubingdisconnects make use of springs or washers that restrict the insidediameter of the tubing string, or leave a connection in the well thatcannot be easily reconnected without special tools. Some tubingdisconnects leave a ball or other activation device in the well that caninhibit additional work that may be required after recovery of the upperunstuck tubing section.

Various current tubing disconnects are intended for very specificapplications. Often, the environment in which these tubing disconnectsare operated is relatively stable and predictable. For example, suchtubing disconnects are intended for releasing perforating guns afterfiring, sub-sea risers, or coiled tubing drilling bits. However, suchtubing disconnects do not have the ruggedness and are not designed tooperate in the extremes of rotary drilling. Such tubing disconnectsoften include mechanical features that a driller would recognize as aweak link in a rotary drill stem.

Some current tubing disconnects include pressure activation, requiringthe ability to circulate fluids within the well tubing. Pressureactivated tubing disconnects are typically activated by dropping orpumping a ball or like device to engage a seat, so that pressure may beapplied down the tubing to initiate disconnection. Without circulation,differential pressure cannot be reliably established to disconnect thetubing. The seat is a restriction to and subject to damage by thepassage of instruments such as measurement while drilling tools and thelike. Accidental impact of tools passing the seat may initiateinadvertent and unwanted disconnection. If the well tubing is plugged, acirculation port must be opened before disconnection is possible. Acirculation port degrades the reliability and pressure integrity of thetubing.

In the process of drilling a well, a drill bit and drill stem may drilla significant distance into the earth without requiring removal andrefitting of a new drill bit. It is problematic to determine where toinstall a disconnect within the drill stem. Deciding the optimumlocation of a disconnect requires an accurate estimation of the probabledepth of the portion of the drill stem that has become stuck. Thisproblem is compounded because a disconnect is lowered progressivelydeeper as the well is drilled. The tubing or drill stem may become stuckdue to solids, such as sand, falling out of well fluid suspension at anydepth within a well.

The several embodiments described herein overcome these and otherlimitations in the art. By way of example, and in no way limiting thescope of this disclosure, a downhole tubular string disconnect mechanismin accordance with the principles disclosed herein may be configured forselective activation within the well bore, meet industry standardsand/or expectations of ruggedness for rotary drilling and other downholeapplications, be insensitive to the passage of instruments and tools,not require well fluid circulation, not require pressure application tothe drill stem, not leave an obstructed well bore after disconnection,and allow disconnection of a drill stem at selectable, multiplelocations by installing multiple disconnects along the length of thedrill stem and providing the ability to disconnect the lowest one in theunstuck portion of the drill stem. Other limitations are also overcome,including for cylindrical member couplings such as for drive shafts.

Nomenclature

The words up, upper, upward or upwardly refer to a direction, portion,motion or action that is closer to the surface of the earth and/orcloser to the surface of the water and/or that which is further from thebottom of the well.

The words down, lower, downward or downwardly refer to a direction,portion, motion or action that is further from the surface of the earthand/or further from the surface of the water and/or that which is closerto the bottom of the well.

“Rotary shouldered threaded connection” (RSTC) is a tubular connectionwith rotationally engaged threads and one or more contacting shouldersto limit engagement and relative movement between two tubulars or pipes.

“Tool joint” is a heavy coupling element utilizing a rotary shoulderedconnection. A tool joint in a drill stem typically has coarse taperedthreads and sealing shoulders designed to sustain the weight of thedrill stem, withstand the strain of repeated make-up and break-out,resist fatigue, resist additional make up during drilling and provide aleak proof seal. API specifications include a series of numbered tooljoint designs; however, proprietary tool joint designs exist that aredifferent from the numbered tool joints of API that include rotaryshouldered connections.

“Drill stem” is an assembly of components joined by tool joints for usein a well for rotary drilling. Components such as a drill bit, a bitsub, drill collars, crossover subs, drill pipe, kelley valves, a swivelsub, a swivel and the like are included. “Drill string” is a length ofconnected drill pipes used for drilling. As previously described,“tubing” refers to those conveyances used for coiled tubing drilling,well completion, workover, and other services less demanding than rotarydrilling. The terms “tubular member” or “tubular string” refer to all ofthe various pipes and strings mentioned above regardless of theirspecific application in the well.

“Minimum make-up torque” is the minimum amount of torque necessary todevelop an arbitrary derived tensile stress in the external thread orcompressive stress in the internal thread of a tool joint. Thisarbitrary derived stress level is perceived as being sufficient in mostconditions to prevent downhole make-up and to prevent shoulderseparation from bending loads.

“Friction factor” is a value that represents the coefficient of frictionof mating surfaces within a threaded connection and the relativemagnitude of assembly torque required to achieve a recommended stresslevel in an assembled connection, as specified by the API.

“Torque turn” is a technique of recording assembly torque and rotationas a thread connection is assembled or disassembled. The collected datais usually analyzed on a computer with specialized software.

“Washout” is a portion of borehole enlarged by erosion of high velocityfluid flow or leakage.

SUMMARY

An assembly for disconnecting and removing an upper portion of a drillstem or tubular string from a well is represented by the variousembodiments herein. The drill stem or tubular string may become stuck inthe well, and the disconnect assembly may be used to separate an upperportion of the drill stem from a lower, stuck portion of the drill stem.In one embodiment, the disconnect assembly (also referred to as a drillstem disconnect or DSD) comprises an upper body and a lower bodyconnected by a rotary shouldered threaded connection (RSTC), wherein theassembly is adapted to be installed as part of a rotary drill stem. Itis understood that the drill stem may be other various kinds of tubularstrings, and the RSTC may be other kinds of joints such asnon-shouldered joints and joints not meeting specific API standards,without affecting the principles disclosed herein.

The RSTC may be configured to assemble at a lower torque than otherconnections within the drill stem and meet the requirements of accepteddrilling industry standards. The RSTC may be configured to assemble withrotation in either direction. The DSD may be configured to withstand thefatigue caused by dynamic tensile, compressive and rotational loadsexperienced within a rotary drill stem. The upper and lower bodies, whenin a locked position, may be blocked from relative rotation by a thirdbody engaging the upper and lower bodies after proper torque has beenapplied, thereby assuring retention of proper assembly torque andallowing the transmission of torque equal to the other connections ofthe drill stem. The third body may be locked in place and may beselectively released and moved from blocking engagement of the upper andlower bodies.

An activation tool, or unlocking and unblocking tool (UUT), mayselectively unlock and move the third body out of blocking engagementwith at least one of the upper or lower bodies, to allow rotation fordisengaging the upper and lower bodies. The tool may be powered byhydrostatic pressure within the well bore. Circulation of well fluidsmay not be required and pressure need not be applied to the well. Anembodiment of the tool may include a selective anchor allowing any oneof multiple identical drill stem disconnects installed in the drill stemto be unlocked and unblocked. The UUT may be configured such that it isretained and removed with the upper body and the upper disconnectedportion of the drill stem. After removal of the upper disconnectedportion of the drill stem, the upward facing connection of the lowerbody, remaining in the well, is unobstructed, facilitating re-attachmentof a later deployed string or tool.

A drill stem tool joint depends on proper assembly torque to achieveoptimum performance. If all tool joints in a drill stem similarlyconfigured, then they are typically assembled with the same torque. Ifthe tool joints within a drill stem vary in size, proprietary design,material properties and the like, then they must be assembled with aminimum make up torque value that exceeds the torque value required tobe transmitted during drilling operations. If a joint cannot withstandthis level of assembly or make up torque, then the joints are sometimesbonded using epoxy compounds. Assembly torque may need to be greater andvary along the length of drill stem to prevent tensile and bending loadsfrom separating the rotary shoulders within a tool joint.

The torque required to disassemble a particular tool joint is a functionof assembly torque. More assembly torque results in more disassemblytorque necessitated to disassemble the tool joint. Furthermore, tooljoints may tighten when in use because of jarring and/or impact of theworking drill bit, temperature effects on thread lubricants, and time ofuse.

When a drill stem becomes stuck within the well bore, it is problematicto determine where along the length of drill stem that reverse torquewill disengage a tool joint.

It is possible, within the parameters and equations specified within API7G, to have tool joints of equal strength that require different minimumassembly torque. For instance, differing friction factors and othervariables within the equations specified within API 7G can individuallyor in combination provide similar variations of required minimumassembly torque. If the equal strength, but lower assembly torque tooljoint is rotationally blocked from further assembly or disassembly, itcan be used in a drill stem at higher torque levels.

An example of this concept is to assemble identical tool joints withlubricants of different friction factors, the high torque tool jointsassembled with high friction factor grease and the low assembly torquejoints assembled with low friction factor grease and subsequentlydisposed to be rotationally blocked from further assembly ordisassembly. However, a tool joint assembled with low torque and notrotationally blocked will disassemble with low torque. Thus a stuckdrill string will disassemble, through reverse rotation of the upperun-stuck drill string, at an unblocked low assembly torque tool jointlocation. A rotationally blocked, low assembly torque tool joint thatfacilitates selective, within-the-well-bore un-blocking, can facilitatethe removal of the upper unstuck drill stem and yet satisfy industrystandards, such as API 7G, when rotationally blocked.

It is common to utilize so called “Torque Turn” techniques to assureproper assembly of tool joints. This technique accurately measures thetorque as a tool joint is rotated during assembly. Those with ordinaryskill in the art are aware that, during assembly, there is very littlerotation after the rotary shoulders achieve minimum torque as contact ismade, and there is little additional rotation to achieve maximum torque.

Those with ordinary skill in the art understand that each time a tooljoint is assembled, disassembled and reassembled that variations inangular position between the halves of the tool joint are common due towear, variations of lubricant thickness and the like.

In some embodiments, a disconnect assembly includes an upper body and alower body connected by a rotary shouldered threaded connection, adaptedto be installed as part of a rotary drill stem. The rotary shoulderedthreaded connection is adapted to assemble at a lower torque than otherconnections within the drill stem and meet the requirements of accepteddrilling industry standards. The rotary shouldered threaded connectionmay be configured to assemble with rotation in either direction. Theassembly is designed to withstand the fatigue caused by dynamic tensile,compressive and rotational loads experienced within a rotary drill stem.The upper and lower bodies are blocked from further rotation by a thirdbody, or rotational blocking sleeve, engaging the upper and lower bodiesafter proper torque has been applied, thereby assuring retention ofproper assembly torque and allowing the transmission of torque equal tothe other connections of the drill stem. The third body is locked inplace and may be selectively released and moved from blockingengagement. A locking assembly has a bore larger than surrounding boresand is thus protected from accidental engagement when well boreinstruments or tools are passed therethrough.

The rotational blocking sleeve or member provides accurate rotationalpositioning between the upper and lower bodies for proper torqueretention. The blocking sleeve accommodates variations of angularalignment when the upper and lower bodies are properly assembled. Insome embodiments, the blocking member is a serrated or splined blockingsleeve that facilitates selective blocking and unblocking of the upperand lower bodies, wherein the upper and lower bodies are joined by a lowassembly torque rotary shouldered threaded connection.

In the embodiments disclosed herein, a method is presented thataddresses one or more of the limitations noted above. The blockingsleeve is moveable to and from blocking engagement with the upper andlower bodies using a sliding fit including a small amount of angularclearance. The splines or first serration of the upper body include adifferent number of teeth, or a different angular pitch, than thesplines or second serration of the lower body. The blocking sleeveincludes accommodating or mating splines or serrations. The blockingsleeve serrations have a progressive, incremental angle between theindividual features or teeth forming the serrations because of thediffering number of teeth or angular pitch. In one embodiment, theincremental pitch between upper and lower serrations on the blockingsleeve is smaller than the total of the angular clearance between theupper body serration and the upper serration of the blocking sleeve plusthe angular clearance between the lower body serration and the lowerserration of the blocking sleeve. Thus, no matter how the upper andlower bodies angularly align, the blocking sleeve may be rotated andmoved into blocking engagement therebetween.

By way of example, if the blocking sleeve has a 50-tooth serration onone axial end and a 51-tooth serration on the other axial end, theincremental angle will be

${\left. \frac{360{^\circ}}{\left( {50 \cdot 51} \right)} \right.\sim 0.14}{^\circ}\mspace{14mu} {({approximately}).}$

Thus, if the total angular clearance is 0.2 degrees, the blocking sleevemay be installed for any angular orientation of the upper and lowersplines and the maximum angular deviation from nominal is 0.2 degrees.It is noted that other angular clearances, both less than and greaterthan 0.2 degrees can be used.

The compressive stress retained in the rotationally blocked rotaryshouldered connection of the assembly embodiments described herein isretained between a minimum and maximum allowed value. So whenconfigured, the upper and lower bodies or subs of the disconnectassembly disclosed herein may be torqued to a specific or predeterminedvalue and, without rotational adjustment, the blocking sleeve may beengaged.

In some embodiments, the blocking sleeve is retained in the engagedposition by a locking mechanism that transfers impact and vibrationforces directly from the blocking sleeve to the upper and lower bodiesof the assembly. The locking mechanism is held and selectively releasedin response to forces applied by the unlocking and unblocking tooldisclosed herein.

In some embodiments, an unlocking and unblocking tool selectivelyunlocks and moves the sleeve out of blocking engagement between theupper or lower bodies, to allow rotation to disengage the upper andlower bodies of the drill stem disconnect assembly. The UUT is poweredby hydrostatic pressure within the well bore. Circulation of well fluidsis not required and pressure need not be applied to the well. The UUTincludes a selective anchor allowing any one of multiple identical drillstem disconnects installed in the drill stem to be unlocked andunblocked. The activating UUT is configured such that it is retained andremoved with the upper body and the upper disconnected portion of thedrill stem. After removal of the upper disconnected portion of the drillstem, the upward connection of the lower body, remaining in the well, isunobstructed, facilitating re-attachment.

In some embodiments, a disconnect assembly includes a first bodyincluding a first serration, a second body including a second serration,and a third body including a third serration to be engaged with thefirst serration using a first number of teeth, and the third bodyinclude a fourth serration to be engaged with the second serration usinga second number of teeth to lock the first body relative to the secondbody. In an embodiment, the third body is free to rotate to align thefirst and third serrations and the second and further serrations priorto movement of the third body to a locking position.

In some embodiments, a disconnect assembly includes a first tubularmember including a first inner serration, a second tubular memberincluding a second inner serration, wherein the first tubular member iscoupled to the second tubular member, and an inner sleeve including anupper serration engaged with the first inner serration with a firstangular pitch, and a lower serration engaged with the second innerserration with a second angular pitch. In an embodiment, the upperserration and the first inner serration each have the same number ofteeth, and the lower serration and the second inner serration each havethe same number of teeth that is different than the number of upperserration teeth. In an embodiment, the engaged upper serration and firstinner serration has a first clearance, the engaged lower serration andsecond inner serration has a second clearance, and the upper and lowerserrations have an incremental pitch less than the sum of the first andsecond clearances.

In some embodiments, a disconnect assembly includes a first tubularmember including a first inner serration, a second tubular memberincluding a second inner serration, an inner sleeve including an upperserration engaged with the first inner serration and a lower serrationengaged with the second inner serration, and a rotary shouldered andthreaded connection coupling the first and second tubular members. In anembodiment, the upper and lower serrations are axially engageable withthe first and second serrations for any rotational position of the innersleeve using a first angular pitch for the upper engaged serration and asecond angular pitch for the lower engaged serration.

In some embodiments, a disconnect assembly includes a first tubularmember including a first inner spline, a second tubular member includinga second inner spline, and an inner sleeve including an upper splineengaged with the first inner spline and a lower spline engaged with thesecond inner spline, wherein the inner sleeve is held into engagementwith the first and second tubular members by a lock.

In some embodiments, a disconnect assembly for a downhole tubular stringincludes a first body connected to a second body with a threadedconnection, a first serration in the first body, a second serration inthe second body, a third body including upper and lower serrations formating engagement with the first and second serrations, the third body,in a first position, prevents rotation between the first and secondbodies, and in a second position allows relative rotation between thefirst and second bodies, and the upper and lower serrations are alignedwith the first and second serrations for movement of the third bodybetween the first and second positions after an assembly torque isapplied to develop a predetermined amount of axial load between thefirst and second bodies. In an embodiment, the third body is free torotate between the first and second positions to align the upper andlower serrations with the first and second serrations for movement ofthe third body into a locking position.

These and other features will be readily apparent to those skilled inthe art upon reading the following detailed description of theembodiments and by referring to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more detailed description of embodiments of the invention,reference will now be made to the accompanying drawings, wherein:

FIG. 1 is an end view defining section views FIGS. 2A, 2B, 2E, and 2F;

FIG. 2A is a section view of the upper most end of the DSD;

FIG. 2B is an intermediate section view of the DSD;

FIG. 2C is an intermediate section view of the DSD;

FIG. 2D is an intermediate section view of the DSD;

FIG. 2E is an intermediate section view of the DSD;

FIG. 2F is a section view of the lower most end of the DSD;

FIG. 3 is a section view, shown in full, defined in FIG. 2C;

FIG. 4 is a section view, shown in full, defined in FIG. 2C;

FIG. 5 is a section view, shown in full, defined in FIG. 2C;

FIG. 6 is a section view, shown in full, defined in FIG. 2D;

FIG. 7 is a section view, shown in full, defined in FIG. 2D;

FIG. 8 is a section view, shown in full, defined in FIG. 2D;

FIG. 9 is an end view defining section views FIGS. 10A, 10B, and 10F;

FIG. 10A is a section view of the upper most end an alternateconstruction DSD;

FIG. 10B is an intermediate section view of the alternate constructionDSD;

FIG. 10C is an intermediate section view of the alternate constructionDSD;

FIG. 10D is an intermediate section view of the alternate constructionDSD;

FIG. 10E is an intermediate section view of the alternate constructionDSD;

FIG. 10F is a section view of the lower most end of the alternateconstruction DSD;

FIG. 11 is a section view, shown in full, defined in FIG. 10A;

FIG. 12 is a section view, shown in full, defined in FIG. 10B;

FIG. 13 is a section view, shown in full, defined in FIG. 10C;

FIG. 14 is a section view, shown in full, defined in FIG. 10C;

FIG. 15 is a section view, shown in full, defined in FIG. 10C;

FIG. 16 is a section view, shown in full, defined in FIG. 10D;

FIG. 17 is a section view, shown in full, defined in FIG. 10D;

FIG. 18 is a section view, shown in full, defined in FIG. 10D;

FIG. 19 is a section view, shown in full, defined in FIG. 10D;

FIG. 20 is a section view, shown in full, defined in FIG. 10D;

FIG. 21 is a section view, shown in full, defined in FIG. 10E;

FIG. 22 is a side view of a blocking sleeve;

FIG. 22A is an end view, defined in FIG. 22;

FIG. 22B is a section view, defined in FIG. 22;

FIG. 22C is a section view, defined in FIG. 22;

FIG. 22D is a detail view, defined in FIG. 22A;

FIG. 23 is a side view of an alternate blocking sleeve;

FIG. 23A is an end view defined in FIG. 23;

FIG. 23B is a section view, defined in FIG. 23;

FIG. 23C is a section view, defined in FIG. 23;

FIG. 23D is a detail view defined in FIG. 23A;

FIG. 24 not used;

FIG. 25A is a section view of the upper most end of the UUT;

FIG. 25B is an intermediate section view of the UUT;

FIG. 25C is an intermediate section view of the UUT;

FIG. 25D is an intermediate section view of the UUT;

FIG. 25E is an intermediate section view of the UUT;

FIG. 25F is an intermediate section view of the UUT;

FIG. 25G is an intermediate section view of the UUT;

FIG. 25H is a section view of the lower most end of the UUT;

FIG. 26 is a section view, shown in full, defined in FIG. 25A;

FIG. 27 is a section view, shown in full, defined in FIG. 25A;

FIG. 28 is a section view, shown in full, defined in FIG. 25A;

FIG. 29 is a section view, shown in full, defined in FIG. 25B;

FIG. 30 is a section view, shown in full, defined in FIG. 25B;

FIG. 31 is a section view, shown in full, defined in FIG. 25B;

FIG. 32 is a section view, shown in full, defined in FIG. 25B;

FIG. 33 is a section view, shown in full, defined in FIG. 25C;

FIG. 34 is a section view, shown in full, defined in FIG. 25D;

FIG. 35 is a section view, shown in full, defined in FIG. 25E;

FIG. 36 is a section view, shown in full, defined in FIG. 25E;

FIG. 37 is a section view, shown in full, defined in FIG. 25E;

FIG. 38 is a section view, shown in full, defined in FIG. 25E;

FIG. 39 is a section view, shown in full, defined in FIG. 25E;

FIG. 40 is a section view, shown in full, defined in FIG. 25F;

FIG. 41 is a section view, shown in full, defined in FIG. 25F;

FIG. 42 is a section view, shown in full, defined in FIG. 25F;

FIG. 43 is a section view, shown in full, defined in FIG. 25F;

FIG. 44 is a section view, shown in full, defined in FIG. 25G;

FIG. 45 is a section view, shown in full, defined in FIG. 25G;

FIG. 46 is a section view, shown in full, defined in FIG. 25G;

FIG. 47A is a partial section view of the UUT as shown in FIG. 25A andFIG. 25B; as it is lowered through a drill stem above the DSD as shownin FIG. 2A and FIG. 2B;

FIG. 47B is a partial section view of the UUT as shown in FIG. 25A andFIG. 5B; as it is lowered within the DSD as shown in FIG. 2B and FIG.2C;

FIG. 47C is a partial section view of the UUT as shown in FIG. 25A andFIG. 5B; as it is lowered further within the DSD as shown in FIG. 2B andFIG. 2C;

FIG. 47D is a partial section view of the UUT as shown in FIG. 25A andFIG. 25B; as it is lifted within the DSD from below as shown in FIG. 2Band FIG. 2C;

FIG. 47E is a partial section view of the UUT as shown in FIG. 25A andFIG. 25B; as it is lifted further within the DSD from below as shown inFIG. 2B and FIG. 2C;

FIG. 47F is a partial section view of the UUT as shown in FIG. 25A andFIG. 25B; as it is lifted even further within the DSD from below asshown in FIG. 2A and FIG. 2B;

FIG. 47G is a partial section view of the UUT as shown in FIG. 25A andFIG. 25B; after landing in the DSD as shown in FIG. 2A and FIG. 2B;

FIG. 48A is a section view of the upper most end of the UUT landed inthe DSD;

FIG. 48B is an intermediate section view of the UUT landed in the DSD;

FIG. 48C is an intermediate section view of the UUT landed in the DSD;

FIG. 48D is an intermediate section view of the UUT landed in the DSD;

FIG. 48E is a section view of the lower most end of UUT landed in theDSD;

FIG. 49A is a section view of the upper most end of the UUT landed inthe DSD;

FIG. 49B is an intermediate section view of the UUT locked in the DSD;

FIG. 49C is an intermediate section view of the UUT locked in the DSD;

FIG. 49D is an intermediate section view of the UUT locked in the DSD;

FIG. 49E is a section view of the lower most end of UUT locked in theDSD;

FIG. 50A is a section view of the upper most end of the UUT activated,the DSD unlocked and unblocking initiated;

FIG. 50B is an intermediate section view of the UUT activated, the DSDunlocked and unblocking initiated;

FIG. 50C is an intermediate section view of the UUT activated, the DSDunlocked and unblocking initiated;

FIG. 50D is an intermediate section view of the UUT activated, the DSDunlocked and unblocking initiated;

FIG. 50E is a section view of the lower most end of UUT activated, theDSD unlocked and unblocking initiated;

FIG. 51A is a section view of the upper most end of the UUT, the lockingsleeve released and the blocking sleeve further moved;

FIG. 51B is an intermediate section view of the UUT, the locking sleevereleased and the blocking sleeve further moved;

FIG. 51C is an intermediate section view of the UUT, the locking sleevereleased and the blocking sleeve further moved;

FIG. 51D is an intermediate section view of the UUT, the locking sleevereleased and the blocking sleeve further moved;

FIG. 51E is a section view of the lower most end of UUT, the lockingsleeve released and the blocking sleeve further moved;

FIG. 52A is a section view of the upper most end of the UUT, theblocking sleeve fully moved and released;

FIG. 52B is an intermediate section view of the UUT, the blocking sleevefully moved and released;

FIG. 52C is an intermediate section view of the UUT, the blocking sleevefully moved and released;

FIG. 52D is an intermediate section view of the UUT, the blocking sleevefully moved and released;

FIG. 52E is a section view of the lower most end of UUT, the blockingsleeve fully moved and released;

FIG. 53A is a section view of the upper most end of the UUT, theblocking sleeve released, the tool extended and pressures equalized;

FIG. 53B is an intermediate section view of the UUT, the blocking sleevereleased, the tool extended and pressures equalized;

FIG. 53C is an intermediate section view of the UUT, the blocking sleevereleased, the tool extended and pressures equalized;

FIG. 53D is an intermediate section view of the UUT, the blocking sleevereleased, the tool extended and pressures equalized;

FIG. 53E is a section view of the lower most end of UUT, the blockingsleeve released, the tool extended and pressures equalized;

FIG. 54A is a section view of the upper most end of the UUT, the drillstem disconnected and the unblocking and unblocking tool being liftedfrom the well bore;

FIG. 54B is an intermediate section view of the UUT, the drill stemdisconnected and the unblocking and unblocking tool being lifted fromthe well bore;

FIG. 54C is an intermediate section view of the UUT, the drill stemdisconnected and the unblocking and unblocking tool being lifted fromthe well bore;

FIG. 54D is an intermediate section view of the UUT, the drill stemdisconnected and the unblocking and unblocking tool being lifted fromthe well bore;

FIG. 54E is a section view of the lower most end of UUT, the drill stemdisconnected and the unblocking and unblocking tool being lifted fromthe well bore;

FIGS. 55-71 are similar sections view as above showing multiplealternative embodiments of both the DSD and the UUT; and

FIGS. 72-88 are elevation and section views of alternative embodimentsof a disconnect assembly in accordance with the principles of thisdisclosure.

DETAILED DESCRIPTION

Referring collectively to FIGS. 1, 2A-2F, 3-8, 22 and 22A-22D, anembodiment of a drill stem disconnect assembly 50 and a blocking sleeve3 are illustrated. The drill stem disconnect assembly 50 (FIG. 2B)includes a generally tubular shape with an outer surface 51. An upperbody or sub 1 is connected to a lower body or sub 2 (FIG. 2C) by a tooljoint 15. Tool joint 15 is a heavy coupling element utilizing a rotaryshouldered and threaded connection.

Referring to FIG. 2A, upper body 1 includes an internal upper thread 1c, often called a female thread or a box thread, which is half of a tooljoint for connection within a drill stem. The axial lower end of lowerbody 2 (FIG. 2F) includes an external lower thread 2 c, often called amale thread or pin thread, which is the other half of a tool joint forconnection within a drill stem.

Referring to FIGS. 2A-2F, upper body 1 has an upper shoulder 1 f (FIG.2A) displaced from lower shoulder 1 b (FIG. 2B) by an internal recess 1h which is axially above internal diameter 1 a; forming landing profile1 l. To allow passage for an unlocking and unblocking tool (UUT),internal diameter 1 a is smaller than tool joint internal diameter 1 k(FIG. 2A), internal diameter of the passage of the drill stem aboveupper body 1, internal diameter 3 a (FIG. 2C) of blocking sleeve 3,internal diameter 2 g of lower body 2 and the internal diameter of thepassage of the drill stem below lower body 2. are larger than internaldiameter 1 a, to allow passage of an unlocking and unblocking tool (UUT)and will be addressed during the discussion of the operation of theassembly below. Axially opposing shoulders 1 i and 3 k form a recess 1j. Internal recess 1 j and internal diameter 1 g are important to thefunction of the UUT, as will be described.

Tool joint 15 may be designed or specially lubricated such that it isproperly assembled at a lower torque than other tool joints in a drillstem. Upper thread 1 c (FIG. 2A) and lower thread 2 c (FIG. 2F) are partof tool joints and form tool joints of a drill stem (not shown). Thesetool joints and others of the drill stem may be designed or lubricatedto properly assemble at a higher assembly torque than that required toassemble tool joint 15.

Serration or splines 1 d (FIGS. 2C and 3) within upper body 1 andserrations or splines 2 d (FIGS. 2C and 5) within lower body 2 may beformed in different manners such as, but not limited to, milling,shaping, electro discharge machining and the like. Internal diameter 1 ais smaller than serration 1 d, and internal diameter 2 g is smaller thanserration 2 d; it may be practical to form serration 1 d and serration 2d in upper body 1, while forming lower body 2 individually when notassembled at tool joint 15. As previously described, alignment ofserration 1 d and serration 2 d when tool joint 15 is properly assembledmay vary because of manufacturing tolerances, wear, thickness oflubrication and the like.

Referring to FIGS. 2C, 3, and 5, blocking sleeve 3 (FIG. 2C) is disposedradially within upper body 1 and lower body 2. Blocking sleeve 3 hasupper serration or splines 3 b radially engaged with compatible ormating serration 1 d of upper body 1 and lower serration or splines 3 c(FIG. 2C) engaged with compatible or mating serration 2 d of lower body2. Upper serration 3 b of blocking sleeve 3 and serration 1 d of upperbody 1 are complementary and have angular clearance 13 (FIG. 3)configured for sliding engagement; accordingly, they may have the samenumber or angular pitch serration. Lower serration 3 c of blockingsleeve 3 and serration 2 d of lower body 2 are complementary and haveangular clearance 13 a (FIG. 5) configured for sliding engagement;accordingly, they may have the same number or angular pitch serration.

Upper serration 3 b of blocking sleeve 3 and serration 1 d of upper body1 have a different number or angular pitch than lower serration 3 c ofblocking sleeve 3 and serration 2 d of lower body 2. Angular clearance13 (FIG. 3) added with angular clearance 13 a (FIG. 5) results in aclearance that is greater than incremental pitch 14 (FIG. 22D) betweenlower serration 3 c and upper serration 3 b.

Referring to FIGS. 22 and 22A-22D, the incremental pitch 14 (FIG. 22D)between serration 3 b and serration 3 c of blocking sleeve 3 is shownadjacent to aligned set of teeth 14 a (though alignment is not necessaryfor the pitch increment). FIGS. 22C and 22B illustrate serration 3 c andserration 3 b respectively, while FIG. 22A illustrates both serration 3b and serration 3 c as viewed from the axial end of FIG. 22. In thisparticular embodiment, serration 3 b includes 50 teeth while serration 3c includes 51 teeth. Serration 3 b and serration 3 c include a set ofaligned teeth 14 a. Due to the difference in the number of teeth betweenserration 3 b and serration 3 c, the set of teeth 14 b (FIG. 22D)circumferentially adjacent to aligned set 14 a are not angularly alignedlike the aligned set of teeth 14 a, but instead are out of phase by theamount of incremental pitch 14. Additional sets of teeth along thecircumference of serrations 3 b and 3 c will be further out of phase,with the next additional set circumferentially adjacent to set 14 b outof phase by twice the incremental pitch, the next circumferentiallyadjacent set out of phase by triple the incremental pitch, etc., untilserration 13 b and serration 13 c are completely out of phase at a pointalong the circumference of serrations 3 b and 3 c diametrically opposedto aligned set of teeth 14 a. In this embodiment, serration 1 d (FIG. 3)includes 50 teeth (matching serration 3 b) and serration 2 d (FIG. 5) oflower body 2 includes 51 teeth (matching serration 3 c), mirroring theincremental pitch 14 a of serration 3 b and 3 c of blocking sleeve 3.

Having the same incremental pitch, serration 1 d and serration 2 d,regardless of angular alignment, will include sets of teeth in phase andsets of teeth incrementally out of phase, with the incremental shiftinto and out of phase by each set of teeth governed by the incrementalpitch. Thus, aligning the in phase sets of teeth of serrations 3 b and 3c with the corresponding in phase sets of teeth of serrations 1 d and 2d allows upper serration 3 b to engage serration 1 d simultaneously withthe engagement between lower serration 3 c and serration 2 d, regardlessof the rotational alignment of serration 1 d and serration 2 d when tooljoint 15 is properly assembled. Thus, it may not be necessary tocompromise desired assembly torque to adjust the angular alignment ofupper body 1 and lower body 2 for engagement with blocking sleeve 3, norare match-fit parts required.

Blocking sleeve 3, so engaged, prevents relative rotation between upperbody 1 and lower body 2. Referring to FIGS. 2C and 2D, blocking sleeve 3includes an upper seal surface 3 e, lower seal surface 3 f, intermediategap 3 d, internal diameter 3 a, upper end 3 g of upper serration 3 b,lower end 3 h of lower serration 3 c, upper end 3 j, and lower end 3 i.Blocking sleeve 3 may be prevented from axial upward movement byengagement between upper end 3 j of blocking sleeve 3 and shoulder 1 eof upper body 1. Blocking sleeve 3 is prevented from being displacedaxially lower by lower end 3 i engaging “c” ring 5, which may bedisposed axially below blocking sleeve 3.

Tool joint 15 is sealed by the contact of the rotary shouldersincorporated therein, while upper seal 10 within groove 1 m and lowerseal 12 within groove 2 j function as debris barriers and maintainlubrication of serrations 1 d, 3 b, 2 d and 3 c. Upper seal surface 3 emay be the same or very nearly the same diameter as lower seal surface 3f to assure ease of movement in a high hydrostatic pressure fluidenvironment.

Now referring to FIG. 2D, “c” ring 5 is held in a radially expandedcondition within groove 2 a of lower body 2 by support surface 4 c oflock sleeve 4. Filler “c” ring 9, which serves to assist in assembly, isconfigured to be inserted within groove 2 e in order to trap andtransfer loads from retaining ring 8 and lower body 2. Ring 7 and shockabsorber 6, which is possibly made of elastomeric material, secure locksleeve 4 in position for lock sleeve 4 to axially support “c” ring 5 andtransfer loads axially from lock sleeve 4 to retaining ring 8. Retainingring 8 is robust and may require a force to shear. In an exemplaryembodiment, tens of thousands of pounds of force may shear the retainingring 8. Lock sleeve 4 is lighter than blocking sleeve 3 and thus willcreate proportionately smaller inertial forces when subjected to theforces of rotary drilling. Shock absorber 6 protects retaining ring 8from the affects of vibration and impact shock that take place duringrotary drilling.

Axial gap 16 between “c” ring 5 and the axial upper end of lock sleeve 4assures that forces acting to move blocking sleeve 3 downward aretransferred from blocking sleeve 3, through “c” ring 5, to the shoulder2 b of groove 2 a of lower body 2. Internal diameter 3 a of blockingsleeve 3 may be smaller than internal diameter 4 a of lock sleeve 4,thereby providing protection from forces associated with loweringservice tools through the drill stem, such as measurement while drillingtools and the like. Internal diameter 3 a may be larger than internaldiameter 1 a, which may provide clearance to internal surfaces duringthe functioning of a UUT, which will be addressed during the discussionof the operation of the assembly below.

As will be discussed below, blocking sleeve 3 may be unlocked bydisplacing lock sleeve 4 axially downward. A UUT engages shoulder 4 b oflock sleeve 4, forcibly compelling shoulder 4 d to axially compressshock absorber 6 and force ring 7 to shear retaining ring 8. Afterretaining ring 8 is sheared, forming an outer portion 8 a which remainsin groove 2 e and an inner portion 8 b which moves downwardly ahead oflock sleeve 4, the UUT displaces lock sleeve 4 downwardly into aposition where support surface 4 c is no longer in position to axiallysupport “c” ring 5 in the radially expanded position within groove 2 aof lower body 2.

Subsequently, a UUT axially engages upper shoulder 3 k (FIG. 2C) andforces blocking sleeve 3 downwardly. As blocking sleeve 3 is displaceddownwardly, “c” ring 5 is forced downwardly and out of groove 2 a while“c” ring 5 continues to forcibly compel lock sleeve 4 and inner portion8 b downwardly. With continued axial downward movement, upper serration3 b radially expands and passes through “c” ring 11, carried withingroove 2 h of lower body 2. Blocking sleeve 3 is prevented from furtherdownward displacement when lower end 3 i of blocking sleeve 3, actingthrough “c” ring 5, lock sleeve 4, shoulder 4 d, shock absorber 6, ring7 and inner portion 8 b, engages shoulder 2 f of lower body 2.

Blocking sleeve 3, upon being fully displaced axially downward,serration 1 d of upper body 1 is disengaged from upper serration 3 b(FIG. 2C) of blocking sleeve 3 and lower serration 3 c is disengagedfrom serration 2 d of lower body 2. Accordingly, upper end 3 g of upperserration 3 b is now disposed axially below “c” ring 11, preventingupper serration 3 b of blocking sleeve 3 from returning to engagementwith serration 1 d of upper body 1. Torque applied in the oppositerotational direction from torque applied during assembly will causerotation between upper body 1 and lower body 2, assuming the portion ofdrill stem below lower body 2 is stabilized, such as by being stuck inthe well bore, and thus will be prevented from rotation in eitherdirection. Continued rotation in the rotational direction opposite ofthat used in the assembly of tool joint 15 and lifting of the upperunstuck drill stem will disconnect the drill stem at tool joint 15.

Filler ring 9 (FIG. 2D) may aid in assembly. Initially filler ring 9 isdisposed within bore 2 i (FIG. 2E). Retaining ring 8, ring 7, shockabsorber 6, lock sleeve 4, “c” ring 5 and blocking sleeve 3 aredisplaced downward by a UUT until retaining ring 8 engages shoulder 2 fof lower body 2. In this configuration, lower serration 3 c of blockingsleeve 3 and serration 2 d of lower body 2 are disengaged and upper body1 may be properly assembled to lower body 2. After proper torque isapplied at tool joint 15, blocking sleeve 3 may be rotated for splineengagement, as discussed more fully above, and displaced upwardly untilupper end 3 j engages shoulder 1 e of upper body 1. Subsequently, “c”ring 5, forcibly compelled by lock sleeve 4, is displaced upwardly andwhen it reaches groove 2 a (FIG. 2D) “c” ring 5 radially expands andallows lock sleeve 4 to pass underneath “c” ring 5 and radially support“c” ring 5 with support surface 4 c. Thereafter, filler ring 9 isdisplaced axially upward to engage shock absorber 6 and retaining ring 8with shoulder 4 d of lock sleeve 4. In this position, filler “c” ring 9may radially expand and engage shoulder 2 f of lower body 2.

Filler “c” ring 9 includes hole 9 a and hole 9 b to facilitate removalof filler “c” ring 9 from the recess within lower body 2 disposedimmediately above shoulder 2 f. Likewise, “c” ring 5 includes hole 5 aand hole 5 b to facilitate removal of “c” ring 5 from lower body 2. “C”ring 11 has hole 11 a and hole 11 b for the same purpose.

Alternative embodiments of a drill stem disconnect assembly including ablocking sleeve are illustrated with reference to FIGS. 9, 10A-10F,11-21, 23, and 23A-23D. The alternative embodiments described belowinclude some differences from the embodiments described above withreference to FIGS. 1, 2A-2F, 3-8, 22, and 22A-22D.

It may be desirable, for certain sizes and tool joint designs, to formthe internal body serrations with a broach. Referring to FIGS. 10A-10E,internal diameters 18 b, 18 e, 18 f and 18 g and internal diameters 27 g(FIG. 10C), 27 i, 27 m (FIG. 10D), 27 n, 27 o, 27 p, 27 q (FIG. 27E) and27 r are sufficiently diametrically large to allow the forming ofserration 18 a (FIG. 10C) and serration 27 d by displacing a broach withprogressively larger teeth axially through an upper sub 18 (FIG. 10B)and a lower sub 27 (FIG. 10C). Serration 18 a disposed within upper sub18 and serration 27 d disposed within lower sub 27 may be formed indifferent manners such as, but not limited to, broaching, milling,shaping, electro discharge machining and the like.

An upper body 17 (FIG. 10A) may be assembled as a sub-assembly. Upperbody 17 includes: upper sub 18 with ring 24 (FIG. 10C) positionedagainst shoulder 18 d, spacer 22 trapped axially by “c” ring 19 (FIG.19), and bushing 20 with a seal 25 that seals between bushing 20 andupper sub 18, with the bushing 20 trapped axially between “c” ring 19and “c” ring 21 (FIG. 10A). Collectively, these components forming upperbody 17 may be interchangeable with upper body 1 of FIGS. 2A and 2B.

A lower body 26 (FIG. 10E) may also be assembled as a sub-assembly.Lower sub 27 includes: “c” ring 45 disposed within groove 27 j,removable shoulder 29 (FIG. 10D) including first arc piece 29 a, shortarc piece 29 b and second arc piece 29 c, installed in groove 271,removable shoulder 28 (FIG. 17) including first arc piece 28 a (FIG.18), short arc piece 28 b and second arc piece 28 c, installed in groove27 k (FIG. 10D), collectively form lower body 26, which may beinterchangeable with lower body 2 of FIGS. 2C-2F.

Referring collectively to FIG. 9, 10A, 10B-10F, 11-21, 23 and 23A-23D,upper body 17 is connected to lower body 26 by tool joint 33 (FIG. 10C).Tool joint 33 may be a rotary shouldered and threaded connection.

Upper sub 18 is shown to have an internal upper thread 18 c (FIG. 10A)often called a female thread or a box thread, which is half of a tooljoint for connection within a drill stem (not shown). The lower end oflower sub 27 is shown to have an external lower thread 27 c (FIG. 10F)often called male thread or pin thread, which is the other half of atool joint for connection within a drill stem (not shown).

Referring to FIGS. 10C and 10D, blocking sleeve 41 (FIG. 10C) isdisposed within upper sub 18 and lower sub 27. Blocking sleeve 41includes upper serration 41 b engaged with compatible or matingserration 18 a of upper sub 18 and lower serration 41 c engaged withcompatible or mating serration 27 d of lower sub 27. Upper serration 18a and serration 41 b are complementary and have angular clearance 42(FIG. 13) for sliding engagement; accordingly, upper serration 18 a andserration 41 b may have the same number or angular pitch serration.Lower serration 41 c and serration 27 d are complementary and haveangular clearance 42 a (FIG. 15) for sliding engagement; accordingly,lower serration 41 c and serration 27 d may have the same number orangular pitch serration.

Upper serration 41 b and serration 18 a of upper sub 18 have a differentnumber or angular pitch than lower serration 41 c and serration 27 d oflower sub 27. The summation of angular clearance 42 (FIG. 13) andangular clearance 42 a (FIG. 15) is greater than the incremental pitch43 (FIG. 23D) between lower serration 41 c and upper serration 41 b(FIG. 10C). As best seen in FIGS. 23 and 23A-23D, incremental pitch 43(FIG. 23D) between serration 41 b and 41 c of blocking sleeve 41 (FIG.10C) is shown adjacent to aligned teeth 43 a (FIG. 23D) (thoughalignment is not necessary for the pitch increment). Blocking sleeve 41may be rotated such that engagement between upper serration 41 b andserration 18 a of upper sub 18 occurs simultaneously with engagementbetween lower serration 41 c and serration 27 d of lower sub 27,regardless of the rotational alignment of serration 18 a and serration27 d when tool joint 33 is properly assembled. Thus, it may not benecessary to compromise desired assembly torque to adjust the angularalignment of upper sub 18 and lower sub 27 for engagement with blockingsleeve 41, nor are match-fit parts required.

Bushing 20 (FIG. 10B) includes an upper shoulder 20 c (FIG. 10A) axiallydisplaced from lower shoulder 20 b (FIG. 10B) by an internal recess 20 ewhich is disposed axially above internal diameter 20 a; thus, a landingprofile 20 h is formed for landing and anchoring a UUT. Internaldiameter 18 b (FIG. 10A), which is the internal diameter of the passageof the drill stem axially above upper sub 18, internal diameter 41 a(FIG. 10C) of blocking sleeve 41, and internal diameter of the drillstem axially below may all be greater in diameter than internal diameter20 a, in order to allow for the passage of a UUT. Shoulder 20 f (FIG.10B) and shoulder 41 k (FIG. 10C) form recess 22 b. Recess 22 b anddiameter 20 d provide radial clearance for the functioning of a UUT.These features and their relationship with the UUT will be addressedduring the discussion of the operation of the assembly below.

Tool joint 33 may be configured or specially lubricated such that it isproperly assembled at a lower applied torque than other tool joints in adrill stem. Upper thread 18 c of upper sub 18 and lower thread 27 c oflower sub 27 are part of and form tool joints of a drill stem (notshown). These tool joints and others of the drill stem are configured orlubricated to properly assemble at a higher applied assembly torque thantool joint 33.

Blocking sleeve 41 is disposed within upper sub 18 and lower sub 27.Blocking sleeve 41 includes upper serration 41 b that may be configuredto engage compatible or mating serration 18 a of upper sub 18, and lowerserration 41 c that may be configured to engage compatible or matingserration 27 d of lower sub 27. Blocking sleeve 41, when engaged, mayprevent relative rotation between upper sub 18 and lower sub 27.Blocking sleeve 41 also includes upper seal surface 41 e, lower sealsurface 41 f (FIG. 10D), intermediate gap 41 d (FIG. 10C), internaldiameter 41 a, upper end 41 g of upper serration 41 b, lower end 41 h oflower serration 41 c, upper end 41 j and lower end 41 i (FIG. 10D).Blocking sleeve 41 is prevented from upward axial displacement by upperend 41 j engaging shoulder 22 a of spacer 22. Internal recess 22 b (FIG.10C) is disposed axially above shoulder 22 a. Blocking sleeve 41 isprevented from downward axial displacement by engagement between lowerend 41 i and “c” ring 36 (FIG. 10D).

Tool joint 33 is sealed by the contact of the rotary shouldersincorporated therein, while upper seal 23 and lower seal 32 function asdebris barriers and maintain lubrication of serrations 18 a, 41 b, 27 dand 41 c. Upper seal surface 41 e may be the same or very nearly thesame diameter as lower seal surface 41 f to assure ease of movement in ahigh hydrostatic pressure fluid environment.

Referring to FIG. 10D, “c” ring 36 is held in a radially expandedcondition within groove 27 a of lower sub 27 by support surface 35 c oflock sleeve 35. Filler “c” ring 40 may be configured to be insertedwithin groove 27 e in order to trap and transfer loads from retainingring 39 and lower sub 27. Ring 38 and shock absorber 37, which ispossibly made of elastomeric material, secure lock sleeve 35 in positionfor lock sleeve 35 to axially support “c” ring 36 and transfer loadsaxially from shoulder 35 d of lock sleeve 35 to retaining ring 39.Retaining ring 39 is robust and may require a force to shear. Inexemplary embodiments, the force may be tens of thousands of pounds.Lock sleeve 35 is lighter than blocking sleeve 41 and thus will createproportionately smaller inertial forces when subjected to the forces ofrotary drilling. Shock absorber 37 protects retaining ring 39 from theaffects of vibration and impact shock that take place during rotarydrilling.

Axial gap 44 between “c” ring 36 and the axial upper end of lock sleeve35 assures that forces acting to move blocking sleeve 41 downward aretransferred from blocking sleeve 41, through “c” ring 36, to theshoulder 27 b of groove 27 a of lower sub 27. Internal diameter 41 a ofblocking sleeve 41 may be smaller than internal diameter 35 a of locksleeve 35, thereby providing protection from forces associated withlowering service tools through the drill stem, such as measurement whiledrilling tools and the like. Internal diameter 20 a may be smaller thaninternal diameter 41 a of blocking sleeve 41.

Blocking sleeve 41 may be unlocked by displacing lock sleeve 35 axiallydownward. A UUT engages shoulder 35 b of lock sleeve 35, forciblycompelling shoulder 35 d to axially compress shock absorber 37 and forcering 38 to shear retaining ring 39. After retaining ring 39 is sheared,forming an outer portion 39 a which remains in groove 27 e and an innerportion 39 b which moves downwardly ahead of lock sleeve 35, the UUTdisplaces lock sleeve 35 downwardly into a position where supportsurface 35 c is no longer in position to axially support “c” ring 36 inthe radially expanded position within groove 27 a of lower sub 27.

Subsequently, a UUT axially engages upper shoulder 41 k (FIG. 10C) andforces blocking sleeve 41 axially downward. As blocking sleeve 41 isdisplaced downwardly, “c” ring 36 is forced downwardly and out of groove27 a while “c” ring 36 continues to forcibly compel lock sleeve 35 andinner portion 39 b downwardly. With continued axial downward movement,upper serration 41 b radially expands and passes through “c” ring 34,carried within groove 27 h of lower sub 27. Blocking sleeve 41 isprevented from further downward displacement when lower end 41 i ofblocking sleeve 41, acting through “c” ring 36, lock sleeve 35, shockabsorber 37, ring 38, inner portion 39 b, and shoulder 45 a of “c” ring45, engages shoulder 27 s of lower sub 27.

Blocking sleeve 41, upon being fully displaced axially downward,serration 18 a of upper sub 18 is disengaged from upper serration 41 bof blocking sleeve 41 and lower serration 41 c is disengaged fromserration 27 d of lower sub 27. Accordingly, upper end 41 g of upperserration 41 b is now disposed axially below “c” ring 34, preventingupper serration 41 b of blocking sleeve 41 from returning to engagementwith serration 18 a of upper sub 18. Torque applied in the oppositerotational direction from the torque applied during assembly will causerotation between upper sub 18 and lower sub 27, as long as the portionof drill stem below lower body 26 is stuck or otherwise stabilized suchthat it will not rotate or move axially up or down. Continued rotationin the rotational direction opposite of that used in the assembly oftool joint 33 and lifting of the upper unstuck drill stem willdisconnect the drill stem at tool joint 33.

Filler ring 40 (FIG. 2D) may aid in assembly. Initially filler ring 40is disposed within internal diameter 27 q (FIG. 2E). Retaining ring 39,ring 38, shock absorber 37, lock sleeve 35, “c” ring 36 and blockingsleeve 41 are displaced downward by a UUT until retaining ring 39engages shoulder 45 a of “c” ring 45. In this configuration, lowerserration 41 c of blocking sleeve 41 and 18 a of upper sub 18 aredisengaged and upper sub 18 may be properly assembled to lower sub 27.After proper torque is applied at tool joint 33, blocking sleeve 41 maybe rotated for spline engagement, as discussed more fully above, anddisplaced upwardly until upper end 41 j engages shoulder 22 a of spacer22. Subsequently, “c” ring 36, forcibly compelled by lock sleeve 35, isdisplaced upwardly. When “c” ring 36 reaches groove 27 a it radiallyexpands and allows lock sleeve 35 to pass underneath and radiallysupport “c” ring 36 with support surface 35 c. Thereafter, filler ring40 is displaced axially upward to engage shock absorber 37 and retainingring 39 with shoulder 35 d of lock sleeve 35. In this position, filler“c” ring 40 may radially expand and engage shoulder 27 f of lower sub27.

Filler “c” ring 40 includes hole 40 a and hole 40 b to facilitateremoval of filler “c” ring 40 from the groove 27 e within lower sub 27.Likewise, “c” ring 36 includes hole 36 a and hole 36 b to facilitateremoval of “c” ring 36 from lower sub 27. “C” ring 34 includes hole 34 aand hole 34 b, “c” ring 19 has hole 19 a and 19 b, “c” ring 21 has hole21 a and 21 b, “c” ring 45 has hole 45 b and 45 c for the same purpose.

In further embodiments, it is also possible to assemble upper sub 18 andlower sub 27 with the proper assembly torque and requisite lubricant,then using a broaching process, to configure serration 18 a andserration 27 d to achieve aligned angular registry therebetween. In thisinstance, blocking sleeve 41 may be manufactured with upper serration 41b and lower serration 41 c aligned and matching. The installation of allother components may be made without disassembling tool joint 33.

Referring collectively to FIGS. 25A-25H and 26-46, embodiments of anactivation tool, unlocking and unblocking tool, or UUT 90 areillustrated. Referring initially to FIGS. 25A-25H, an upper end includesa fishing neck 100 (FIG. 25A) connected to a mandrel 101 by threads 102.Mandrel 101 is connected to upper control tube 103 (FIG. 25B) by threads104, which is connected to intermediate control tube 105 (FIG. 25F) bythreads 106 (FIG. 25E), which is connected to lower control tube 107(FIG. 25G) with threads 108. A body 109 (FIG. 25A) is connected to core110 (FIG. 25B) by threads 111, which is connected to upper coreextension 112 (FIG. 25F) by threads 135 (FIG. 25E), which is connectedto core adapter 113 (FIG. 25F) by threads 114, which is connected tointermediate core extension 115 (FIG. 25G) by threads 116 (FIG. 25F),which is connected to lower core adapter 117 (FIG. 25G) by threads 118,which is connected to lower core extension 119 (FIG. 25H) by threads120.

The interaction of shoulder 101 g (FIG. 25A) with shoulder 109 s providean up stop, and the interaction of end surface 101 h (FIG. 25B) with endsurface 110 a provide a down stop, respectively, limiting the relativemotion between the mandrel 101 and body 109 during the functioning ofthe UUT, and will be further addressed during the discussion of theoperation of the assembly below.

Grapple 121 (FIG. 25C) is connected to upper barrel 122 (FIG. 25E) bythreads 123 with connector 124 clamped therebetween. Upper barrel 122 isconnected to intermediate barrel 125 (FIG. 25G) by threads 126 (FIG.25F) with intermediate connector 127 therebetween. Intermediate barrel125 (FIG. 25G) is connected to protector 128 (FIG. 25H) by threads 129(FIG. 25G) with lower connector 130 (FIG. 25H) therebetween.

Referring to FIGS. 25B and 32, collet 131 (FIG. 25B) is connected byshear pin 132 in hole 131 p and hole 133 a to lower ring 133. Shear pin152 is located opposite and is functionally identical to shear pin 132.Upper ring 134 contacts shoulder 1090 and spring 151.

Referring to FIGS. 25A and 28, key 136 (FIG. 25A) is radially movable inwindow 109 a of body 109. Radial outward motion of key 136 is limited byshoulder 136 a, shoulder 136 b and bore 109 d. Radial inward movement ofkey 136 is limited by surface 136 c contacting diameter 101 a. Key 137,key 138 and key 139 (FIG. 28) are functionally identical and fitted formovement within body 109 the same as key 136. The interaction of key 136with shoulder 101 f and diameter 101 e will be addressed further duringthe discussion of the operation of the assembly below.

Referring to FIGS. 25A and 27, “c” ring 140 is in groove 101 b,contacting shoulder 109 e and limiting upward movement of mandrel 101with respect to body 109. “C” ring 140 is biased radially outward butrestrained from expansion by bore 109 f. The function of groove 109 gwill be addressed during the discussion of the operation of the assemblybelow. Hole 140 a and hole 140 b facilitate assembly and disassembly.

Referring to FIGS. 25B and 29, a bore sensor 142 is disposed in the body109. Bore sensor 142 is radially movable in hole 1091. “C” ring 141 iswithin groove 101 c and groove 109 h preventing mandrel 101 from movingdown with respect to body 109. “C” ring 141 is biased radially outward,pushing sensor 142 outward. Radial outward motion of bore sensor 142 isstopped by flange 142 a contacting groove 109 h. Bore sensors 143, 144,145, 146 and 147 (FIG. 29) are functionally similar and fitted formovement within body 109 the same as bore sensor 142.

Referring to FIGS. 25B and 30, “C” ring 148 is in groove 109 k and isbiased radially outward against bore 131 a. Ball 150 is radially movablein hole 1091 and urged radially outward by “c” ring 149 which is withingroove 109 m and groove 101 d. “C” ring 149 prevents downward movementof mandrel 101 with respect to body 109. Ball 154, ball 155, ball 156,ball 157 and ball 158 (FIG. 30) are functionally identical and fittedfor movement within body 109 the same as ball 150.

Referring to FIG. 25B, spring 151 forcibly compels collet 131, shear pin132 and lower ring 133 downwardly. The limit of downward motion is lowerring 133 contacting core 110. Spring 151 is sufficiently forceful toovercome friction between “c” ring 148 and bore 131 a. Lower ring 133 isfree to move upwardly against spring 151 along diameter 109 n. Spring151 also urges upper ring 134 upwardly. Upper ring 134 is prevented fromupward movement along diameter 109 n by shoulder 109 o.

Collet 131 has finger 131 d with lower external shoulder 131 e, lowerinternal shoulder 131 f, upper external shoulder 131 g, upper internalshoulder 131 h, internal surface 131 i and external surface 131 j. Thefunctional interface of lower internal shoulder 131 f of collet finger131 d with diameter 109 p and shoulder 109 q of body 109 will beaddressed during the discussion of the operation of the assembly below.In FIG. 25B, finger 131 d is not biased inwardly for contact betweeninternal surface 1311 and diameter 109 p. Collet 131 has fingers 131 k,1311, 131 m, 131 n and 1310 (FIG. 29) that are similar and functionallythe same as finger 131 d.

Referring to FIGS. 25C, 33 and 25D, 34, upper finger 121 a (FIGS. 25Cand 33) may be relaxed and in the inward position shown in FIG. 25C,with internal surface 121 e adjacent diameter 110 b. Lower finger 121 f(FIGS. 25D and 34) may be relaxed and in the inward position shown inFIG. 25D, with internal surface 121 j adjacent diameter 110 f. Upperfinger 121 n, upper finger 121 o, upper finger 121 p, upper finger 121 qand upper finger 121 r (FIG. 33) are similar and functionally the sameas upper finger 121 a. Lower finger 121 s, lower finger 121 t, lowerfinger 121 u, lower finger 121 v and lower finger 121 w (FIG. 34) aresimilar and functionally the same as lower finger 121 f.

Referring to FIG. 25E, fluid passage 121 l, 103 a and 110 k assure fluidcommunication and equal pressure between the radially outer and innercylindrical surfaces of grapple 121. Shear screw 159 is secured withinthreaded hole 121 m and within groove 110 j, locating grapple 121axially along core 110.

The interrelationship of external shoulder 121 b, external surface 121d, external surface 121 i, external shoulder 121 g, lower externalshoulder 131 e, external surface 131 j and shoulder 136 d with the DSD50 of FIGS. 1, 2A-2F, 3-8, 22, and 22A-22D will be addressed during thediscussion of the operation of the assembly below.

Referring to FIGS. 25E and 25F, chamber 179 is formed by seal surface112 a, seal 168, connector 124, seal 172, seal bore 122 a, seal 173 andcore adapter 113. Fluid passage 113 a and the leak path of thread 114are sealed by seal bore 112 b, seal 160, intermediate control tube 105,seal 161 and seal bore 113 b.

Referring to FIG. 25F, chamber 180 is formed by seal surface 115 a, seal169, intermediate connector 127, seal 174, seal bore 122 a, seal 173 andcore adapter 113. Fluid passage 113 c and the leak path of thread 116are sealed by seal bore 113 b, seal 162, intermediate control tube 105,seal 163 and seal bore 115 b.

Referring to FIGS. 25F-25H, chamber 181 (FIG. 25G) is formed by sealsurface 115 a, seal 169, intermediate connector 127, seal 175, seal bore125 a, seal 176 and lower core adapter 117. Fluid passage 117 a and theleak path of thread 118 are closed by seal bore 115 b, seal 164, lowercontrol tube 107, seal 165 and seal bore 117 b. Chamber 182 (FIG. 25H)is formed by seal surface 119 a, seal 170, lower connector 130, seal178, seal bore 125 a, seal 176 and lower core adapter 117. Fluid passage117 c and the leak path of thread 120 are sealed by seal bore 117 b,seal 166, lower control tube 107, seal 167 and seal bore 119 b.

Referring to FIGS. 25A-25H, fluid passage 183 (FIG. 25H) extends throughthe interior of protector 128, seal bore 119 b to seal 167, lowercontrol tube 107 (FIG. 25G), through fluid passage 107 a, seal bore 117b between seal 165 and seal 166, intermediate control tube 105 (FIG.25F), through fluid passage 105 b, seal bore 115 b between seal 163 andseal 164, through fluid passage 105 a, seal bore 113 b between seal 161and seal 162, upper control tube 103 (FIG. 25E), through fluid passage103 a, which is open to hydrostatically pressurized fluid 184 (FIG.25H), mandrel 101 (FIG. 25A), fishing neck 100 and thru fluid passage100 a. When submerged deep within a fluid filled well, highhydrostatically pressurized fluid 184 may enter fluid passage 183 andsurround chamber 179 (FIG. 25E), chamber 180 (FIG. 25F), chamber 181(FIG. 25G) and chamber 182 (FIG. 25H).

Seal bore 119 b (FIG. 25H), seal bore 117 b (FIG. 25G), seal bore 115 b,seal bore 113 b (FIG. 25F) and seal bore 112 b, are substantially thesame. There is no or very little force caused by high hydrostaticallypressurized fluid 184, as would exist deep within a fluid filled well,to move the fishing neck 100 up or down.

As assembled, chamber 179, chamber 180, chamber 181 and chamber 182contain air at or near the atmospheric pressure in which they wereassembled. Seal surface 112 a (FIG. 25F) and seal surface 119 a (FIG.25H) are the same or very nearly the same diameter; thus, there is abalancing upward force acting on lower connector 130 against a downwardforce acting on connector 124 (FIG. 24E).

Referring to FIG. 25E, grapple 121 and core 110 are designed such thathigh pressure fluid 184 surrounding the UUT may not result in thesevering of shear screw 159.

Referring to FIGS. 25A-25H, as will be more fully described in thediscussion of operation of the assembly below, the net result ofallowing hydrostatically pressurized fluid 184 into chamber 180 and 182would be to urge grapple 121 downward and to equally urge body 109upward.

Allowing hydrostatically pressurized fluid 184 within chamber 180 (FIG.25F) creates a downward force on intermediate connector 127 and anupward force on core adapter 113. Allowing hydrostatically pressurizedfluid 184 within chamber 182 (FIG. 25H) eliminates the upward force uponlower connector 130 that acted to balance the downward force upon coreadapter 124 (FIG. 25E), which creates an upward force on lower coreadapter 117 (FIG. 25G).

The functional interrelationship of the relative longitudinal positionof the fishing neck 100 with respect to body 109 and the affected fluidpassages 113 a, 105 a, 113 c, 105 b, 117 a, 107 a and 117 c and relatedchambers 179, 180, 181, and 182 will be addressed during the discussionof the operation of the assembly below.

The interrelationship and operation of UUT 90 shown in FIGS. 25A-25H and26-46 with the DSD 50 shown in FIGS. 1, 2A-2F, 3-8, 22 and 22A-22D isdiscussed below as if being used in a hypothetical well.

Functionally identical items disclosed in FIGS. 25A, 25B, 28-30 and 32will not be mentioned below for brevity. In the following discussion,key 136 will be inclusive of functionally identical key 137 (FIGS. 25Aand 28), key 138, and key 139. Bore sensor 142 (FIGS. 25B and 29) willbe inclusive of functionally identical bore sensor 143, bore sensor 144,bore sensor 145, bore sensor 146 and bore sensor 147. Ball 150 (FIGS.25B and 30) will be inclusive of functionally identical ball 154, ball155, ball 156, ball 157 and ball 158. Shear pin 152 (FIGS. 25B and 32)will be inclusive of functionally identical shear pin 153.

In an exemplary embodiment, a well includes multiple DSD's installed atintervals along the length of a rotary drill stem. The spacing, numberand location Of the DSD's is based on a risk analysis by thoseresponsible for the drilling program. For example, one DSD may beconnected between every nine joints of drill pipe, starting at twothousand feet above the drill bit and continuing to the surface. Thus,there would be twelve disconnects in the well. Further, the drill pipecould be stuck such that the drill pipe will not move up or down, cannotbe rotated and circulation of drill fluids is not possible. The pipecould then be stretched and relaxed to hypothetically determine that thepipe is stuck below the eighth DSD.

In such an exemplary situation, a UUT 90 would be connected to aconventional wireline unit, with appropriate weight bar, jars, runningtool and the like (not shown), via the fishing neck 100.

Referring to FIGS. 2A-2C, 25A, 25B, 47A-47G, the UUT 90 is lowered, thenraised and lowered again within the well drill stem. “C” ring 140 (FIG.25A) is within groove 101 b and shoulder 109 e receives the weight ofthe UUT 90 and transmits upward forces from the wireline (not shown) inall of the motions. During the movements of the UUT 90, mandrel 101 andbody 109 do not move relative to one another and thus the lower portionsof the UUT 90 are inactive.

FIG. 47A shows the portion of the UUT 90 described previously in FIG.25B, as it is received within the first DSD 50 of the twelve identicalDSD's of this exemplary situation. Arrow 186 indicates the direction ofthe axial motion of UUT 90. Outer diameter 110 m of core 110 slidesaxially through internal diameter 1 a of upper body 1, with a clearanceexisting between the two diameters. The external surface 131 j passesthrough internal diameter 1 g with a clearance existing between the twodiameters. Bore 131 a prevents the radially outward biased “c” ring 148from expanding outwardly, and because of ball 150, radially outwardbiased “c” ring 149 is prevented from expanding outwardly. “C” ring 149is within groove 101 d and groove 109 m, preventing relative movementbetween mandrel 101 and body 109. Bore sensor 142 is radially displacedoutward by “c” ring 141 and is disposed within groove 101 c and 109 h,preventing relative movement between mandrel 101 and body 109. Shear pin132 remains unsevered and spring 151 forcibly urges collet 131 downward.

FIG. 47B shows the portion of the UUT 90 described previously in FIG.25B, as it is lowered further into the DSD 50 and downwardly displacedfrom its position illustrated in FIG. 47A, but still within the first ofthe twelve identical DSD's of this exemplary situation. Arrow 186indicates the direction of motion of the UUT 90. As UUT 90 is displaceddownward from the position in FIG. 47A to the position in FIG. 47B,lower exterior shoulder 131 e contacts lower shoulder 1 b, forciblypreventing collet 131 from further travelling downward. As the UUT 90 islowered further through the drill stem, diameter 109 p slides underinternal surface 131 i compressing spring 151 until finger 131 d is nolonger supported by diameter 109 p. Subsequent downward lowering of body109 further compresses spring 151 and causes finger 131 d to radiallydeflect inward, sliding radially down shoulder 109 q and subsequentlymove axially downward, sliding along internal diameter 1 a. Bore sensor142 is displaced radially inward by lower shoulder 1 b, displacing “c”ring 141 radially deeper within groove 101 c and out of engagement withgroove 109 h. Bore 131 a prevents “c” ring 148 from expanding radiallyoutward, and because of ball 150, “c” ring 149 is prevented fromexpanding radially outward. “C” ring 149 is within groove 101 d andgroove 109 m, preventing relative axial movement between mandrel 101 andbody 109. Shear pin 132 remains unsevered and spring 151 forcibly urgescollet 131 downward.

FIG. 47C shows continued downward movement of the UUT 90 through the DSD50. As UUT 90 is displaced downward from the position of FIG. 47B to theposition of FIG. 47C, upper external shoulder 131 g slides axiallydownward and radially outwards along shoulder 1 i and external surface131 j moves axially out of internal diameter 1 a. Shear pin 132 isremains unsevered and spring 151 forcibly moves collet 131 downward to aposition of lower ring 133, causing collet 131 to contact core 110.Finger 131 d moves radially outward to a relaxed position with internalsurface 131 i radially adjacent diameter 109 p. Bore sensor 142 returnsto the radial outward position by the outward urging of radially biased“c” ring 141 as “c” ring 141 returns to its initial position withingroove 101 c and groove 109 h, preventing relative axial movementbetween mandrel 101 and body 109. Bore 131 a prevents “c” ring 148 fromradially expanding outward, and because of ball 150, “c” ring 149 isprevented from radially expanding outward. “C” ring 149 is disposedwithin groove 101 d and groove 109 m, preventing relative axial movementbetween mandrel 101 and body 109. The UUT 90 has now returned to thecondition as shown in FIG. 47A; however, now in the position shown inFIG. 47C, instead of the outer diameter 110 m of core 110 being withininternal diameter 1 a of upper body 1, outer diameter 110 m of core 110is now within internal diameter 3 a of blocking sleeve 3 with clearance,existing between the two diameters.

As the UUT 90 is moved further down the drill stem it will repeat theabove positioning of components illustrated in FIGS. 47A-47C as itpasses through the internal diameter 1 a of each DSD 50 encountered. TheUUT 90 is thus capable of passing downward through any number of DSD's.

In this exemplary situation, after passing the eighth DSD 50, known tothe wireline operator by a depth indicator at the surface of the well,the UUT 90 is slowly elevated until upper external shoulder 131 g ofcollet 131 contacts shoulder 1 i of the eighth DSD, known to thewireline operator by a weight indicator at the surface of the well.

After confirming the downhole depth, the UUT 90 is lowered downward at ahigh enough acceleration to create sufficient velocity for the momentumof the weight bar, jars, running tool and UUT to sever shear pin 152 ofFIG. 25B.

FIG. 47D shows the portion of the UUT 90 previously described in FIG.25B, as it is raised upward through, but still within, the eighth oftwelve identical DSD's in this exemplary situation. Arrow 188 indicatesthe direction of the upward motion of UUT 90. As UUT 90 is displacedfrom the position of FIG. 47C to the position of FIG. 47D, externalsurface 131 j passes through blocking sleeve 3 with a clearance betweenthe two surfaces, and upper external shoulder 131 g contacts shoulder 1i, forcibly preventing collet 131 from any further upward movement.Initially, momentum of UUT 90 carries core 110 upward, which in turnforcibly compels lower ring 133 upward, severing shear pin 132. Further,the lower end of spring 151 no longer pushes collet 131 downward, asshear pin 132 is now severed and lower ring 133 is no longer connectedto collet 131. Spring 151 now acts to radially expand collet 131 as endsurface 134 a of upper ring 134 contacts shoulder 131 b. Body 109 thenbegins moving upward within collet 131, with diameter 109 p movingupward and sliding under internal surface 131 i of collet 131. Core 110moves upward and forcibly compels lower ring 133 to compress spring 151.

As body 109 moves upward in relation to collet 131, “c” ring 148 slidesaxially upward and along bore 131 a and radially outwards into groove131 q, with ball 150 and “c” ring 149 moving radially outwarddisengaging “c” ring 149 from groove 101 d in mandrel 101. However,because bore sensor 142 remains disposed radially outward due to theforce acting on it from outwardly biased “c” ring 141 which resides ingroove 109 h and groove 101 c, axial motion remains inhibited betweenmandrel 101 and body 109. Core 110 continues to move upward, forciblycompelling lower ring 133 to further compress spring 151.

Continued motion of body 109 causes bevel 131 s of collet 131 to deflect“c” ring 148 radially inward, until “c” ring 148 enters a bore 131 t. As“c” ring 148 deflects radially inward, ball 150 forcibly compels “c”ring 149 radially inward such that it is disposed within groove 101 dand groove 109 m, thereby preventing further axial motion betweenmandrel 101 and body 109. Core 110, as it travels upward, forciblycompels lower ring 133 to further compress spring 151.

Continued upward movement of body 109 further compresses spring 151, asdiameter 109 p continues to slide upward and along internal surface 131i until upper internal shoulder 131 h slides downward along shoulder 109r and deflects finger 131 d radially inward, resulting with externalsurface 131 j sliding into internal diameter 1 a. Once external surface131 j of collet 131 slides upward into internal diameter 1 a, lower ring133, forcibly acted upon by core 110, does not compress spring 151 anyfurther.

FIG. 47E shows the position of UUT 90 as it is displaced upward from theposition shown in FIG. 47D, while still within the eighth of twelveidentical DSD's in this exemplary situation. Arrow 188 indicates thedirection of motion of the UUT 90. In this position, outer diameter 110m of core 110 is disposed within internal diameter 3 a of blockingsleeve 3. Bore sensor 142, having been displaced further upward, hasentered internal diameter 1 a and is now displaced radially inward byshoulder 1 i, in turn displacing “c” ring 141 radially inward, deeperwithin groove 101 c and out of engagement with groove 109 h; however,“c” ring 149 is disposed within groove 101 d and 109 m, preventingrelative axial motion between mandrel 101 and body 109. Spring 151 nowurges collet 131 upward. Continued upward motion of UUT 90 axiallydisplaces external surface 131 j of collet 131 upward, within internaldiameter 1 a. Body 109 and mandrel 101 may be further displaced upwardwith external surface 131 j moving axially within internal diameter 1 a.

FIG. 47F shows a portion of UUT 90 as it is displaced upward, above theeighth of the twelve identical DSD's in this exemplary situation. Arrow188 indicates motion of the UUT in either direction. Bore sensor 142,upon exiting internal diameter 1 a due to its upward displacement, isradially displaced outward by “c” ring 141, disposing it within groove101 c and 109 h, preventing relative axial movement between mandrel 101and body 109. During the transition from the position of FIG. 47E to theposition of FIG. 47F, external surface 131 j of collet 131 is displacedupward through internal diameter 1 a, and bore sensor 142 exits internaldiameter 1 a before external surface 131 j because while externalsurface 131 j is in sliding contact with internal diameter 1 a, boresensor 142 is disposed above the lowermost edge of external surface 131j, where external surface 131 j meets lower external shoulder 131 e.Thus, as bore sensor 142 displaces radially outward, “c” ring 141engages groove 101 c and groove 109 h before external surface 131 j ofcollet 131 axially exits internal diameter 1 a, preventing relativeaxial motion between mandrel 101 and body 109.

As collet 131 is displaced upward to exit internal diameter 1 a, lowerexternal shoulder 131 e slides axially along lower shoulder 1 b,allowing finger 131 d to displace radially outward as upper internalshoulder 131 h is displaced radially outwardly as it slides alongshoulder 109 r until internal surface 131 i slides axially alongdiameter 109 p. As collet 131 moves upward relative to body 109, bore131 t slides upward in relation to “c” ring 148, allowing “c” ring 148to radially expand into groove 131 q and ultimately engage shoulder 131r of collet 131. “C” ring 149 radially expands out of groove 101 d asball 150 follows the radial expansion of “c” ring 148. However, becausebore sensor 142 remains radially outward from the urging of radiallybiased “c” ring 141, which is disposed in groove 109 h and groove 101 c,relative axial motion is prevented between mandrel 101 and body 109.

As situated in FIG. 47F, outer diameter 110 m of core 110 is disposedwithin internal diameter 1 a of upper body 1. Spring 151 forciblycompels upper ring 134 axially against shoulder 131 b, axiallydisplacing collet 131 upward such that shoulder 131 r engages “c” ring148 within groove 109 k. Finger 131 d is disposed in the relaxedposition with internal surface 131 i supported on diameter 109 p. “C”ring 141 is disposed radially within both groove 101 c and in groove 109h, preventing relative axial movement between mandrel 101 and body 109.Bore sensor 142 is disposed in a radially outward position. Shear pin132 is severed and spring 151 now urges collet 131 upward.

If UUT 90 is displaced axially upward through another DSD in the drillstem, collet 131 will frictionally engage internal diameter 1 a whilebody 109 continues to travel upward, allowing finger 131 d of collet 131to radially collapse along shoulder 109 r and pass through internaldiameter 1 a of the DS, at which time finger 131 d may radially expandagain to engage diameter 109 p and return to the condition of FIG. 47F.In this manner, the UUT may be raised and removed from the well, passingthru any number of DSDs in the drill stem.

FIG. 47G shows a portion of the UUT 90 as it is axially displaceddownward into the eighth of the twelve identical DSD's in thehypothetical drill stem of this exemplary situation. Arrow 190 indicatesaxial motion of UUT 90. Finger 131 d is disposed in the relaxed positionwith internal surface 131 i supported on diameter 109 p. Lower externalshoulder 131 e of collet 131 engages lower shoulder 1 b and axialdownward movement of the body 109 is prevented by the engagement of “c”ring 148, which is radially disposed within both groove 109 k andshoulder 131 r. While “c” ring 149 is radially disposed outside ofgroove 101 d, Bore sensor 142 is radially disposed within internaldiameter 1 a and has radially displaced “c” ring 141 outwards so that itis no longer disposed within groove 109 h; thus, for the first time inthe sequence of movements of UUT 90 of this exemplary situation,relative axial movement between mandrel 101 and body 109 is possible.

As described in the exemplary situation above, an embodiment of UUT 90may be selectively landed in any one of multiple DSD's and be retrievedfrom the well at any time. In the following description, the functioningof an embodiment of the UUT to unlock and unblock a DSD will beexplained. The following actions performed by an embodiment of the UUTare initiated by relative axial movement of fishing neck 100 withrespect to body 109.

FIGS. 48A-48E, 49A-49E, 50A-50E, MA-ME, 52A-52E, 53A-53E and MA-ME aresectional views showing progressive operation of the components of theembodiment of UUT 90 shown in FIGS. 25A-25H and 26-46 and the embodimentof DSD 50 shown in FIGS. 1, 2A-2F, 3-8, 22 and 22A-22D.

Hydrostatically pressurized fluid 184 is located within fluid passage183, completely surrounding UUT 90, within the drill stem connectedaxially upward of body 1, within DSD 50, and in the stuck drill stemconnected axially downward of lower body 2.

Referring to FIGS. 25A-25H and 26-46, as previously described, fishingneck 100 (FIG. 25A) is connected to mandrel 101, upper control tube 103(FIG. 25C), intermediate control tube 105 (FIG. 25F) and lower controltube 107 (FIG. 25G). Also, body 109 (FIG. 25A) is connected to core 110(FIG. 25B), upper core extension 112 (FIG. 25F), core adapter 113,intermediate core extension 115 (FIG. 25G), lower core adapter 117 andlower core extension 119 (FIG. 25H). Grapple 121 (FIG. 25C) is connectedto upper barrel 122 (FIG. 25E), connector 124, intermediate connector127 (FIG. 25F), intermediate barrel 125 (FIG. 25G), lower connector 130(FIG. 25H) and protector 128.

Referring to FIGS. 48A-48E, collet 131 has landed on and engagedshoulder 1 b, preventing axial downward movement of body 109, as shownin FIG. 48A. Body 109 is connected to grapple 121, by shear screw 159(FIG. 48C).

The weight of the wireline tools has resulted in the axial movement offishing neck 100 (FIG. 48A) downward such that “c” ring 140 is no longerengaging shoulder 109 e of body 109. Shoulder 101 f of mandrel 101 hasmoved axially downward within landing profile 1 l of upper body 1 and isnow disposed radially inwards of radially outwards displaced key 136.Diameter 101 e radially engages key 136 within window 109 a of body 109with shoulder 136 d in proximity of shoulder 1 f. Body 109 is axiallyanchored within landing profile 1 l of upper body 1, as are all partsconnected to it, including, through shear screw 159, grapple 121 (FIG.48C) and all parts connected to it. Although fishing neck 100 has beenaxially displaced in relation to body 109, flow passages 113 a, 113 c,105 a, 105 b, 117 a, 117 c and 107 a are all blocked, as shown in FIG.48D. Chambers 179 (FIG. 48C), 180, 181 and 182 (FIG. 48D) may bepreassembled and thus contain air at or near atmospheric pressure. Sealsurface 112 a (FIG. 49C) and seal surface 119 a (FIG. 49D) may bestructurally similar. Thus, high hydrostatically pressurized fluid 184surrounding DSD 50 and within passage 183, as is present deep within afluid filled well, will not result in the application of forces orrelative motion between grapple 121 and core 110 that would sever shearscrew 159.

All components of the embodiment of DSD 50 are as shown in FIGS. 1,2A-2F, 3-8, 22 and 22A-22D. Referring to FIGS. 48A-48E, diameter 110 bof core 110 (FIG. 48B) is disposed radially adjacent of internal surface121 e of upper finger 121 a. External surface 121 d of upper finger 121a is displaced axially downward from internal diameter 1 a of upper body1, where internal diameter 1 a is smaller than internal diameter 3 a ofblocking sleeve 3, which in turn is smaller than internal diameter 4 aof lock sleeve 4. Diameter 110 f of core 110 is disposed radiallyadjacent of internal surface 121 j of lower finger 121 f. Externalsurface 121 i of lower finger 121 f is displaced downward from internaldiameter 1 a.

Referring to FIGS. 49A-49E, the weight of the wireline tools results inthe downward axial displacement of fishing neck 100 (FIG. 49A) until endsurface 101 h of mandrel 101 engages end surface 110 a of core 110. Dueto this axial displacement, “c” ring 140 has radially expanded withingroove 109 g of body 109 and is no longer radially disposed withingroove 101 b of mandrel 101. Flow passages 113 a, 105 b and 117 a (FIG.49D) remain blocked. Thus, chambers 179 (FIG. 49C) and 181 (FIG. 49D)continue to contain air at or near atmospheric pressure. However,passages 113 c, 105 a, 117 c and 107 a are now in fluid communicationwith hydrostatically pressurized fluid 184 via passage 183 (FIG. 49E).Chamber 180 and chamber 182 now begin to rapidly fill withhydrostatically pressurized fluid 184. As chamber 180 fills withpressurized fluid 184, chamber 180 applies an axial downward force onintermediate connector 127 (FIG. 49D) and an axial upward force on coreadapter 113. As chamber 182 fills with pressurized fluid 184, chamber182 applies an axial downward force on lower connector 130, effectivelyremoving the axial upward force of lower connector 130 acting to balancethe axial downward force of core adapter 124; chamber 182 also appliesan axial upward force on lower core adapter 117. As explained above,filling chamber 180 and chamber 182 with pressurized fluid 184 forciblycompels grapple 121 axially downward and, with equal and oppositemagnitude, forcibly compels body 109 axially upward.

Further, the compulsion of grapple 121 downward and body 109 upwardresults in shear screw 159 being severed, grapple 121 and connectedparts being displaced axially downward, and lower finger 121 f expandingradially outward as internal shoulder 121 h traverses shoulder 110 g ofcore 110. Internal surface 121 j is radially supported by diameter 110 hand shoulder 121 g engages shoulder 4 b of lock sleeve 4. Grapple 121 istemporarily prevented from further axial displacement as retaining ring8 is not yet severed. As internal shoulder 121 c (FIG. 49B) of upperfinger 121 a traverses shoulder 110 c of core 110, internal surface 121e is radially supported by diameter 110 d; thus, external surface 121 dis radially expanded outward and exterior shoulder 121 b is radiallypositioned to contact upper shoulder 3 k of blocking sleeve 3, butspaced axially away for later engagement. This axial spacing assuresthat the forces generated within UUT 90 are not diminished by frictionabout the blocking sleeve 3 and are retained for severing retaining ring8.

The equal and opposite forces generated as pressure rapidly buildswithin chamber 180 and chamber 182 displaces body 109 axially upwarduntil window 109 a engages key 136, and shoulder 136 d engages uppershoulder 1 f of landing profile 1 l within upper body 1. Body 109 isprevented from further upward axial displacement by key 136 and shoulder1 f of upper body 1. Collet 131 does not contact shoulder 1 b. Downwardaxial displacement of grapple 121 is briefly restrained by retainer 8while pressure rapidly builds within chamber 180 and 182.

Referring to FIGS. 50A-50E, pressure within chamber 180 and chamber 182(FIG. 50D) has, at this point, increased sufficiently to sever retainingring 8 into outer portion 8 a and inner portion 8 b (FIG. 50C). Due tothe severing of retaining ring 8, grapple 121 and connected parts havedisplaced axially downward. Surface 121 j of lower finger 121 f,radially supported by surface 110 h with external shoulder 121 gengaging shoulder 4 b, has axially displaced lock sleeve 4 downward suchthat support surface 4 c is no longer axially disposed within “c” ring5. Internal surface 121 e (FIG. 50B) of upper finger 121 a, radiallysupported by diameter 110 d, has been displaced axially downward suchthat external shoulder 121 b engages upper shoulder 3 k of blockingsleeve 3. Blocking sleeve 3 has started displacing downward and lowerend 3 i (FIG. 50C) has forcibly compelled “c” ring 5 axially downward,as shoulder 2 b of lower body 2 radially displaces “c” ring 5 inward toreside axially within bore 2 k.

Referring to FIGS. 51A-51E, after a brief period of time, grapple 121(FIG. 51C) has been further axially displaced downward, such that finger121 f has been radially displaced inward with internal surface 121 j andis now disposed radially adjacent diameter 110 n of core 110. Thus,locking sleeve 4 is no longer engaging grapple 121. Finger 121 a (FIG.51B), with internal surface 121 e radially supported by diameter 110 d,has forcibly compelled blocking sleeve 3 axially downward such thatupper seal 10 no longer engages upper seal surface 3 e.

Referring to FIGS. 52A-52E, after another brief period of time, grapple121 (FIG. 52B) has been further axially displaced downward. Blockingsleeve 3 has been fully displaced downward such that serration 1 d ofupper body 1 is no longer engaging upper serration 3 b of blockingsleeve 3. Further, “c” ring 11, radially adjacent upper seal surface 3 eand axially upward from upper end 3 g of upper serration 3 b, preventsupper serration 3 b from re-engaging serration 1 d. Finger 121 a hasbeen radially displaced inward with internal surface 121 e now disposedadjacent diameter 110 f of core 110. Thus, blocking sleeve 3 is nolonger in engagement with grapple 121. Also, shoulder 136 d (FIG. 52A)no longer engages shoulder 1 f. Collet 131 is again in engagement withshoulder 1 b, preventing downward axial displacement of UUT 90.

Referring to FIGS. 53A-53E, after a brief period of time, grapple 121(FIG. 53C), no longer engaged with either locking sleeve 4 or blockingsleeve 3, has been fully displaced axially downward. Within chambers 179and 181 (FIG. 53D), minor pressure and temperature changes have occurredduring this process to the atmospheric air trapped during assembly ofthe UUT 90. The pressure changes within these two chambers areinsignificant in relation to the high hydrostatic pressures that existdeep within a fluid filled well, and thus the trapped air withinchambers 179 and 181 is considered near atmospheric pressure. Meanwhile,chambers 180 and 182 are filled with hydrostatically pressurized fluid184.

Referring to FIGS. 54A-54E, for the culmination of this process, thedrill stem situated axially upward from upper body 1 (not shown) andupper body 1 are both rotated in the opposite direction from therotational position used to assemble the rotary shouldered and threadedconnection of tool joint 15 (FIG. 54B) and then lifted upward such as todisconnect upper half 15 a of upper body 1 from lower half 15 b of lowerbody 2. Collet 131 engages lower shoulder 1 b and elevates UUT 90 withthe upper unstuck portion of the drill stem. UUT 90 may be upwardlyremoved with the upper drill stem. The wireline unit may be disconnectedand fishing neck 100 left down or up. Passage 183 is open to drainfluids as the drill stem is elevated.

Alternately, as shown in FIGS. 54A-54E, fishing neck 100 may bedisplaced upwardly such that groove 101 b axially passes “c” ring 140,shoulder 101 g of mandrel 101 engages shoulder 109 s of body 109, key136 is radially displaced outward, surface 136 c is radially adjacentdiameter 101 a, and flow passages 113 a, 105 b, 117 a, 113 c, 105 a, 117c and 107 a (FIG. 54D) are now all open to hydrostatically pressurizedfluid 184 via passage 183 (FIG. 54E). Chambers 179, 180, 181 and 182 arefilled with pressurized fluid 184 and are at similar pressures. As suchthere will be no forces or trapped pressures as the UUT is elevated bywireline to the surface.

Referring to FIGS. 25A-25H and 26-46, UUT 90 may be broken apart atthreads 123, 135 and 106 (FIG. 25E) and axially lengthened by adding: anadditional intermediate control tube 105 (FIG. 25F) with seals 160, 161,162 and 163, an additional upper core extension 112, an additional upperbarrel 122 (FIG. 25E), an additional intermediate connector 127 (FIG.25F) with seals 174, 175 and 163, and an additional core adapter 113with seal 173. Reassembly of UUT 90 with this additional segment willadd another atmospheric chamber and another pressurized chamber. Thisaddition may be repeated as many times as desired to allow UUT 90 to beused shallower in a well that cannot be pressurized from the surface.

A DSD and UUT may also include alternative embodiments. For instance,referring to FIGS. 55-57, a DSD 200 includes an axially inverted blockand lock sleeve mechanism including a block sleeve 203 and a lock sleeve204. The positions of block sleeve 203 and lock sleeve 204 are reversedor inverted compared to the similar structures of the DSD 50 shown inFIGS. 2A-2F. Also axially inverted compared to similar components of DSD50 are the first mating serrations 206 and the second mating serrations208 between block sleeve 203 and body 202. DSD 200 also includes a firsttool joint 215 and a second tool joint 214. The other features ofinverted DSD 200 may be substantially the same as those shown anddescribed with reference to DSD 50 of FIGS. 2A-2F.

Referring to FIGS. 58-64, to activate DSD 200, an alternative UUT 250may be used. UUT 250 includes an upper end similar to the same portionof UUT 90 in FIGS. 25A and 25B. UUT 250 also includes an inner core 252and a grapple 254 similar to grapple 121 but with some differences.Grapple 254 includes an upper collet mechanism with a plurality ofcollets fingers 256 (FIG. 58), a lower collet mechanism with a pluralityof collets fingers 260 (FIG. 60) and a shear member 253. However,grapple 254 of UUT 250 is inverted such that engagement members 258, 262of the collet fingers 256 and 260 are directed in the opposite axialdirection relative to the similar members of grapple 121 of UUT 90.Thus, the axially inverted collets of UUT 250 are adapted foroperational interaction with the appropriate portions of the axiallyinverted DSD 200 described above, in a manner similar to that describedabove with respect to UUT 90 and DSD 50.

Furthermore, UUT 250 also includes an axially inverted lower hydraulicand atmospheric chamber portion as compared to UUT 90. A detaileddescription of the lower chamber portion of UUT 90, including chambers179, 180, 181 and 182, is provided with reference to FIGS. 25E-25H.

Referring to FIGS. 61-64, the lower hydraulic and atmospheric chamberportion of UUT 250 is axially inverted such that a connector 270 (FIG.61) is disposed at an upper end of this portion of UUT 250 radiallyinside outer barrel 264, forming a chamber 282. Axially below thislocation is a chamber 281 (FIG. 62) formed between radially outer barrel264 and radially inner core 266. As shown in FIGS. 63 and 64, anintermediate connector 268 partially defines a chamber 280; also, achamber 279 is disposed within this portion of UUT 250 and is partiallydefined by lower connector 272, outer barrel 264 and inner core 266. UUT250 also includes lower end fluid passage 283. The operation of theinverted lower hydraulic and atmospheric chamber portion of UUT 250 issimilar in manner as compared to the corresponding chamber portion ofUUT 90. However, unlike UUT 90 and DSD 50, block sleeve 203 of DSD 200shifts axially upward upon activation of the assembly and thedisconnection is made in a manner similar as previously described withregard to UUT 90 and DSD 50, at the lower tool joint 215 shown in FIG.57.

In further alternative embodiments of the DSD and UUT, other changes maybe made to these assemblies to provide additional functionality andflexibility to the overall system of disconnecting portions of pipestrings. Referring to FIGS. 65 and 66, another alternative DSD 300 isillustrated which is axially inverted and includes a shear or frangiblerelease in place of the lock sleeve. DSD 300 comprises a body 302 (FIG.65) with no tool joint axially adjacent to the upper end of a blocksleeve 303. Instead a tool joint 315 is disposed toward the axiallylower portion of block sleeve 303 (FIG. 66). Disposed axially betweenbody 302 and block sleeve 303 are first mating serrations 306 and secondmating serrations 308, which are axially displaceable to engage ordisengage the upper and lower bodies on either side of the tool joint315 as described herein. Block sleeve 303 includes an axially upperportion 303 a and an axially lower portion 303 b coupled by a threadedconnection 303 c. A lower shearable or frangible release mechanism 310radially engages both block sleeve 303 and body 302 until activation ofthe assembly occurs in response to a UUT as described herein. Upon theapplication of an upward force by a UUT, mechanism 310 shears orreleases to allow the upper end 312 of block sleeve 303 to move axiallyupward into a bore space 314 of body 302 (FIG. 65), thereby axiallydisengaging mating serrations 306, 308, and allowing the upper and lowertubular strings to be disconnected at the tool joint 315. Other featuresof DSD 300 not specifically described herein are consistent withcorresponding features of the DSD's described elsewhere in thisdescription.

Referring to FIGS. 67 and 68, in a further alternative embodiment of DSD300, a DSD 400 is also axially inverted as compared to DSD 50, but alsoincludes a lower lock mechanism 409 (FIG. 68) rather than the shearmechanism 310 of DSD 300. Upon activation of the assembly in response toa UUT as described herein, an upward force is applied to a lock sleeve414 (FIG. 68) and a collet mechanism 410 of the lower lock mechanism409, releasing a block sleeve 403. Lower lock mechanism 409 comprises anaxial lower portion 403 b and an axial upper portion 403 a of blocksleeve 403, coupled by a threaded connection 403 c. The released blocksleeve 403 is displaced axially upward such that an upper end 412 ofblock sleeve 403 is displaced axially into a bore space 414 of a body402 (FIG. 67), thereby axially disengaging mating serrations 406, 408,and allowing the upper and lower tubular strings to be disconnected atthe tool joint 415. Other features of DSD 400 not specifically describedherein are consistent with corresponding features of the DSD's containedelsewhere in this description.

The DSD's 300, 400, include only one rotary shouldered and threaded tooljoint and one lock or release mechanism, thus only requiring one colletmechanism in the respective activating UUT. An alternative embodiment ofa UUT is illustrated in FIGS. 69-71. UUT 450 is designed to activateinverted DSD's 300, 400, and thus it shares many of the same featuresand characteristics of the previously described UUT 250. For example,the upper fishing neck and collet portion of UUT 450 corresponds to thefishing neck and collet portion of UUT's 50, 250, of FIGS. 25A and 25B.Also, the lower chamber portion of UUT 450 corresponds to the lowerchamber portion of UUT 250, shown in FIGS. 61-64. However, UUT 450includes a grapple 454 (FIG. 70) with only a single collet mechanismincluding a plurality of collets fingers 456 and a shear member 453. Theaxially inverted collet mechanism includes engagement members 458 of thecollet fingers directed in the axially opposed direction of theengagement members of the grapple 121 of UUT 90. The collet mechanism ofthe UUT 450 is configured for operational interaction with the single,lower release or lock mechanism of the inverted DSD's 300, 400,described above.

Another embodiment of a disconnect assembly relates to the use ofserrations to rotationally couple two bodies of a disconnect assemblyusing a third body with a varying number of serrations on each body, andis shown in FIGS. 72-77. First body 500 (FIG. 72) may be a solid orhollow object of any shape fitted with a generally cylindrical end withserrations 500 a disposed radially about an outer circumference of firstbody 500. Second body 501 may be a solid or hollow object of any shapefitted with a generally cylindrical end with serrations 501 a disposedradially about an outer circumference of second body 501. Serrations 500a of first body 500 and serrations 501 a of second body 501 are ofdifferent count or pitch. A third body 502 is fitted with serrations 502a disposed radially about an inner circumference of third body 502 forcompanion engagement with serrations 500 a of first body 500, andserrations 502 b disposed radially about the inner circumference ofthird body 502 but axially displaced from serrations 502 a for companionengagement with serrations 501 a of second body 501.

Sufficient axial clearance must be provided such that serrations 502 aand 502 b of third body 502 may disengage from their respective matingserrations 500 a and 501 a, to allow third body 502 to be rotatedindependently of first body 500 and second body 501. Axial gap 503disposed axially upward from serration 500 a must be of sufficient widthto allow the third body 502 to be axially displaced upward to disengageserration 502 a from serration 500 a of first body 500 and, assumingserration 502 b would interfere by engaging serration 500 a, axial gap504 between serrations 500 a and 501 a must be sufficient to allow thethird body 502 to be axially displaced upward to disengage serration 502b from serration 501 a of second body 501.

Screws 505 a and 505 b retained by nuts 506 a and 506 b extend radiallythrough second body 502, holding third body 502 in the engaged positionas shown in FIG. 72.

If first body 500 and second body 501 are immovable or positioned in adesired rotational position with respect to one another, the third body502, axially positioned such that serration 502 a is aligned in gap 503and serration 502 b is aligned in gap 504, may be rotated into aparticular position and axially engaged with the serrations of the firstbody 500 and the second body 501 by axially displacing third body 502such that serration 502 a engages serration 500 a and serration 502 bengages serration 501 a, to prevent rotation between first body 500 andsecond body 501.

The accuracy of alignment between third body 502 and first and secondbodies 500 and 501 is dependent on the clearance between the bodies andnumber of or pitch of the serrations as previously described.

While keeping with the principles of this disclosure, the first body 500and the second body 501 may be shaft couplings within a machine or asign post and a ground fitting. In further embodiments, the bodies 500,501 include not just downhole tubulars, but tubular or cylindricalmembers in fields outside of hydrocarbon exploration and production.

Also keeping with the principles of this disclosure, if serrations 502 bof third body 502 and 501 a of second body 501 are sufficientlydiametrically larger than serrations 500 a of first body 500 and 502 aof third body 502, gap 504 may be eliminated as larger diameterserration 502 b may be disposed radially over serration 500 a withoutengaging smaller diameter serration 500 a. Additionally, if first body500 may be displaced axially upward and away from second body 501 farenough to disengage third body 502 from both the first body 500 and thesecond body 501, as in the situation of bolted down machine components,gaps 503 and 504 would not be required and screws 505 a, 505 b, and nuts506 a and 506 b may also not be required.

Yet another embodiment of a disconnect assembly using serrations torotationally couple two bodies using a third body, with a differentnumber of serrations on each body is shown in FIGS. 78-88. The firstbody 507 (FIG. 78) is in the form of a shaft including a key slot 507 b(FIG. 83) disposed axially along the circumference of a central bore 507c and a threaded set screw hole 507 d (FIG. 80) extending radially awayfrom first body 507 for mounting on a shaft 510 disposed concentricallywithin first body 507 using a circumferentially disposed key 511. Firstbody 507 has a serrated face 507 a (FIGS. 82, 83). The second body 508is in the form of a shaft including a key slot 508 b (FIG. 84) disposedaxially along the circumference of a central bore 508 c and a threadedset screw hole 508 d (FIG. 508D) extending radially away from secondbody 508 for mounting on a shaft 512 disposed concentrically withinsecond body 508 using a circumferentially disposed key 513. Second body508 has a serrated face 508 a (FIGS. 84, 85). Serrations 507 a of firstbody 507 and serrations 508 a of second body 508 are of different countor pitch. A third body 509 (FIG. 80) is fitted with serrations 509 a(FIG. 87) disposed on a face of third body 508 for companion engagementwith serrations 507 a of first body 507, and serrations 509 b disposedon an opposite face of third body 508 for companion engagement withserrations 508 a of second body 508.

Circumferentially disposed about the axial engagement between first body507, second body 508, and third body 509 are semi-cylindrical retainers514 and 515 (FIG. 78). Retainer 515 and retainer 514 surround and act tohold first body 507, second body 508 and third body 509 in companionserration engagement. Retainer 515 and retainer 514 are secured inengagement about first body 507, second body 508 and third body 509 bystuds 516 a, 516 b, nuts 517 a, 517 b, 517 c and 517 d (FIG. 81).

With the retainer 514 and retainer 515 removed serrations 507 a of firstbody 507 and serrations 508 a of second body 508 may be disengaged fromthe companion serrations 509 a and 509 b of third body 509 and firstbody 507 and second body 508 may be rotated in relation to one anotherto form a new angular relationship. Retainers 514 and 515 may then bereinstalled as previously described depending on clearances and numberof or angular pitch of the pairs of serrations.

Keeping with the principles of this disclosure, first body 507 andsecond body 508 may be formed integrally with shafts 510 and 512 so longas freedom exists to move the shaft mountings axially apart to positionand engage the serration pairs 509 a and 509 b formed with third body509.

It will be understood that all tool joints of the drill stem includingtool joint 15 of FIG. 2C may be identical but assembled with differentlubricants, or they may be of different design but assembled with thesame lubricant, or a mixture of different designs and lubricants and notdeviate from the scope and spirit of the principles disclosed herein.

The exemplary situation given above is by way of example only, and otherembodiments may include one DSD or any number of DSD's used at anydepth, at regular or random spacing intervals so long as adequatehydrostatic or applied pressure is available. Wireline was used in theexemplary situation to lower and raise the UUT within the drill stem,though other common methods may be used with this description such ascoiled tubing, pump down, macaroni tubing, sand line and the like.Circulation was not possible in the exemplary situation described aboveto display the versatility of the embodiments disclosed herein, thoughcirculation is often desirable and would aid, not inhibit, the functionof the described UUTs.

It will be understood that the lower thread of upper body 1 (FIG. 2A)and the upper thread of lower body 2 (FIG. 2F) could be reversed orinterchanged such that upper body 1 could have an external thread andthe upper end of lower body 2 could have an external thread, and thefunctioning of the tool described herein would not change. Likewise thethreads connecting upper body 1 and lower body 2 could be configured toengage by clockwise or counterclockwise rotation, depending on locationand need of a particular use without deviating from the spirit of theprinciples described herein. Further, the upper thread and lower threadcould be any type or kind of drill stem connection to accommodate anyparticular drill stem.

It will thus be seen, that the disconnect for a well drill stem as wellas the selective anchoring and functioning of the unlocking andunblocking tool of the present description may be adapted to carry outthe ends and advantages mentioned as well as those inherent therein.While some embodiments of the apparatus have been shown for the purposesof this disclosure, numerous changes in the arrangement and constructionof parts may be made by those skilled in the art. All such changes areencompassed within the scope and spirit of the appended claims.

It should be understood by those skilled in the art that the disclosureherein is by way of example only, and even though specific examples aredrawn and described, many variations, modifications and changes arepossible without limiting the scope, intent or spirit of the claimslisted below.

1. A disconnect assembly comprising: a first body including a firstserration; a second body including a second serration; and a third bodyincluding a third serration to be engaged with the first serration usinga first number of teeth, and the third body include a fourth serrationto be engaged with the second serration using a second number of teethto lock the first body relative to the second body.
 2. The disconnectassembly of claim 1 further including a threaded connection between thefirst and second bodies.
 3. The disconnect assembly of claim 2 whereinthe threaded connection includes a rotary shoulder.
 4. The disconnectassembly of claim 1 wherein the third body is free to rotate to alignthe first and third serrations and the second and further serrationsprior to movement of the third body to a locking position.
 5. Thedisconnect assembly of claim 1 wherein the third and fourth serrationsare axially engageable with the first and second serrations for anyrotational position of the third body.
 6. A disconnect assemblycomprising: a first tubular member including a first inner serration; asecond tubular member including a second inner serration; wherein thefirst tubular member is coupled to the second tubular member; and aninner sleeve including an upper serration engaged with the first innerserration with a first angular pitch, and a lower serration engaged withthe second inner serration with a second angular pitch.
 7. Thedisconnect assembly of claim 6 wherein the upper serration and the firstinner serration each have the same number of teeth, and the lowerserration and the second inner serration each have the same number ofteeth that is different than the number of upper serration teeth.
 8. Thedisconnect assembly of claim 6 wherein the engaged upper serration andfirst inner serration has a first clearance, the engaged lower serrationand second inner serration has a second clearance, and the upper andlower serrations have an incremental pitch less than the sum of thefirst and second clearances.
 9. The disconnect assembly of claim 6wherein the coupling between the first and second tubular membersincludes a rotary shouldered and threaded connection.
 10. The disconnectassembly of claim 6 wherein the upper and lower serrations are axiallyengageable with the first and second serrations for any rotationalposition of the inner sleeve.
 11. A disconnect assembly comprising: afirst tubular member including a first inner serration; a second tubularmember including a second inner serration; an inner sleeve including anupper serration engaged with the first inner serration and a lowerserration engaged with the second inner serration; and a rotaryshouldered and threaded connection coupling the first and second tubularmembers.
 12. The disconnect assembly of claim 38 wherein the upper andlower serrations are axially engageable with the first and secondserrations for any rotational position of the inner sleeve using a firstangular pitch for the upper engaged serration and a second angular pitchfor the lower engaged serration.
 13. A disconnect assembly comprising: afirst tubular member including a first inner spline; a second tubularmember including a second inner spline; and an inner sleeve including anupper spline engaged with the first inner spline and a lower splineengaged with the second inner spline; wherein the inner sleeve is heldinto engagement with the first and second tubular members by a lock. 14.The disconnect assembly of claim 13 wherein the inner sleeve is abovethe lock.
 15. A disconnect assembly for a downhole tubular stringcomprising: a first body connected to a second body with a threadedconnection; a first serration in the first body; a second serration inthe second body; a third body including upper and lower serrations formating engagement with the first and second serrations; the third body,in a first position, prevents rotation between the first and secondbodies, and in a second position allows relative rotation between thefirst and second bodies; and the upper and lower serrations are alignedwith the first and second serrations for movement of the third bodybetween the first and second positions after an assembly torque isapplied to develop a predetermined amount of axial load between thefirst and second bodies.
 16. The disconnect assembly of claim 15 whereinthe third body is free to rotate between the first and second positionsto align the upper and lower serrations with the first and secondserrations for movement of the third body into a locking position. 17.The disconnect assembly of claim 15 wherein the assembly torque is lessthan a torque applied to other thread connections within the tubularstring.
 18. The disconnect assembly of claim 17 wherein the third bodyin the first position facilitates transmission of a torque in excess ofthe assembly torque.
 19. The disconnect assembly of claim 15 wherein thethreaded connection between the first and second bodies is lubricated toreduce a makeup torque.
 20. The disconnect assembly of claim 15 whereinthe threaded connection includes a rotary shoulder to limit engagementbetween the first and second bodies, and the rotary shoulder is coatedto reduce an assembly torque.
 21. The disconnect assembly of claim 15wherein the third body is prevented from moving to the second positionby a shear ring.
 22. The disconnect assembly of claim 15 wherein thethird body forms a protective chamber for at least one of theserrations.
 23. The disconnect assembly of claim 15 wherein the thirdbody allows fluid passage around the third body.
 24. The disconnectassembly of claim 15 wherein the third body is held into engagement withthe first and second bodies by a lock.
 25. The disconnect assembly ofclaim 24 wherein the lock includes a c-ring held expanded by a supportsleeve disposed in a groove.
 26. The disconnect assembly of claim 25wherein the support sleeve is held in place by a frangible device. 27.The disconnect assembly of claim 26 wherein the frangible device is aring disposed in a groove.
 28. The disconnect assembly of claim 25wherein an inside diameter of the support sleeve is larger than aninside diameter of the third body.
 29. The disconnect assembly of claim24 wherein the lock is held in place by a frangible device.
 30. Thedisconnect assembly of claim 1 wherein the third body is responsive topressure for movement from the first position to the second position.31. A tool for activating a disconnect assembly comprising: an innertubular member; an outer tubular member surrounding and coupled to theinner tubular member; at least one atmospheric chamber between the innerand outer tubular members; at least one atmospheric chamber between theinner and outer tubular members configured to selectively communicatewith a hydrostatic well pressure; and an outer mechanism to interactwith the disconnect assembly.
 32. The tool of claim 31 wherein the outermechanism includes a grapple having at least one collet mechanism forengaging the disconnect assembly.
 33. The tool of claim 31 wherein thedisconnect assembly comprises: a first tubular member including a firstinner spline; a second tubular member including a second inner spline;and an inner sleeve including an upper spline engaged with the firstinner spline and a lower spline engaged with the second inner spline;wherein the outer mechanism is engageable with inner portions of thefirst tubular member and the inner sleeve.
 34. A tool for activating adisconnect assembly comprising: an inner tubular member; an outertubular member surrounding and coupled to the inner tubular member; anouter mechanism to interact with the disconnect assembly; and a moveablebore sensor coupled to and extending from the outer tubular member. 35.The tool of claim 34 wherein the bore sensor is configured to land in aninner profile of the disconnect assembly.
 36. The tool of claim 34wherein the bore sensor is configured to selectively pass throughanother disconnect assembly and land in the inner profile of theselected disconnect assembly.
 37. The tool of claim 34 wherein thedisconnect assembly comprises: a first tubular member including a firstinner spline; a second tubular member including a second inner spline;and an inner sleeve including an upper spline engaged with the firstinner spline and a lower spline engaged with the second inner spline;wherein the outer mechanism is engageable with inner portions of thefirst tubular member and the inner sleeve.
 38. A disconnect assemblycomprising: a first tubular member coupled to a second tubular memberwith a threaded connection; the first and second tubular membersincluding serrations; a sleeve including serrations for engagement withthe serrations of the first and second tubular members to preventrotation between the first and second tubular members; and an unlockingtool including an atmospheric chamber, wherein the sleeve receives theunlocking tool to activate the sleeve to a position to allow rotationbetween the first and second tubular members.
 39. The disconnectassembly of claim 38 wherein the engaged sleeve and first tubular memberserrations include a first number of teeth, and the engaged sleeve andsecond tubular member serrations include a second number of teethdifferent from the first number of teeth.
 40. The disconnect assembly ofclaim 38 wherein the engaged sleeve and first tubular member serrationsinclude a first angular pitch different from a second angular pitch ofthe engaged sleeve and second tubular member serrations.